Abstract: To address the challenges posed by the expansion of sorghum cultivation, the shortage of rural labor, and the growing demand for raw materials in specific industries, achieving efficient, low-loss mechanized harvesting of sorghum has become an urgent need for the industry’s development. Currently, conventional harvesting equipment (often modified from standard grain combine harvesters) faces a series of significant bottlenecks when operating on tall, easily lodging sorghum: the header inlet is prone to clogging, resulting in poor operational continuity; uncontrolled lodging direction of the stalks leads to severe grain loss at the header; and the threshing system suffers from the contradiction of incomplete threshing and high mechanical damage to grains, with overall performance falling far short of ideal levels. To systematically address these issues, this study conducted collaborative optimization and innovative design of key components for a prototype tracked sorghum harvester. The optimization efforts primarily focused on two core modules: the header and the threshing system. For the header, an innovative straw-diverting and gathering bar collaborative flow-guiding mechanism was designed. This mechanism is based on the theory of enveloping cylinders, the inclined plane sliding model, and the cantilever beam bending model. Theoretical calculations determined the angle between the adjustable stalk-separating bar and the horizontal plane (14.36°) and the minimum effective working length (≥1475.6 mm), ensuring that the stalks slide smoothly along the bar rather than becoming entangled, while physically covering the entire height range of sorghum plants (measured height: 1806.2～2105.4 mm). Additionally, gathering rods designed based on the sliding-cutting principle were added on both sides of the header; their 60°-inclined guide surfaces generate lateral guiding forces, forcibly restricting the lateral movement path of the cut stalks. Furthermore, the layout of the stalk-diverting chains was significantly optimized, configuring the two outer rows of chains on the header’s exterior into a staggered arrangement with “outer high, inner low” positioning. This design is based on the principle of torque balance in mechanics. By altering the points of application of the chain teeth at different heights, it systematically adjusts the direction of the resultant torque exerted on the straw bundles, thereby actively redirecting the direction of stem lodging from outward toward the header to inward, effectively reducing grain loss caused by this phenomenon. Regarding the threshing system, parametric co-optimization was performed on the axial-flow threshing drum. Based on a material throughput model, the number of threshing elements was determined to be 114; a configuration of six tooth plates and a three-head spiral layout was adopted to ensure uniform loading and prevent straw blockages; the optimized drum has a diameter of 620 mm and a length of 1880 mm. The core innovation lies in the design and integration of a “front-dense, rear-sparse” variable-aperture concave plate. The front section of this concave plate features large apertures, working in concert with the relatively dense tooth spacing (90 mm) in the inlet section of the threshing drum to achieve efficient threshing and rapid early separation of grains; while the rear section features smaller apertures, matched with the wider tooth spacing (180 mm) in the outlet section, to adapt to the gradual reduction in material volume within the threshing chamber, promote the rearward conveyance of straw, and reduce the load on the subsequent cleaning system. This structure achieves a gradient change in threshing intensity from strong to weak, ensuring a high threshing efficiency while minimizing the risk of grain breakage. Field trials validated the effectiveness of the synergistic optimization. Under conditions where grain moisture content was approximately 20.12% and stalk moisture content was approximately 67.69%, the optimized prototype demonstrated excellent and stable performance when operating within a range of cutting heights of 300～600 mm and forward speeds of 0.6～1.2 m/s: the total loss rate was controlled between 1.25% and 1.71%, the grain breakage rate was 0.48%～0.72%, and the impurity rate was 0.72%～1.06%. All key performance indicators met or exceeded the requirements of national standards such as the “Technical Specifications for Full-Feed Combine Harvesters.” The prototype operated smoothly without any blockages. In summary, this study effectively addressed the industry challenges of “prone to clogging, high losses, and incomplete threshing” in mechanized sorghum harvesting through the synergistic innovation of the header’s “orderly flow guidance and anti-clogging” technology and the threshing system’s “high-efficiency, low-loss separation” technology. The research findings provide a validated technical solution and practical design reference for the development of specialized, high-efficiency, low-loss harvesting equipment suitable for major sorghum-producing regions.