Abstract: This study addresses the significant resource waste of residual cotton left in fields after mechanical harvesting in Xinjiang, China, alongside the prevalent issues of low collection efficiency and high impurity content in existing pickup machinery. To overcome these challenges, a suspended-type residual cotton pickup device integrating picking, cleaning, and conveying functions was designed and developed. The research, grounded in the material characteristics of cotton and local agronomic practices, utilised the cotton variety Guoxin AW04 cultivated at an experimental site in Xinjiang as the study material. Kinematic analysis guided the structural design and parameter determination of the device's core components: the pickup mechanism, the saw-tooth cleaning unit, and the screw conveyor. The derived design specifications are as follows: the pickup roller speed must exceed 37.4 r/min; the round steel bar diameter of the grate is 30 mm with a spacing of 40 mm; the clearance between the grate bars and the tooth tips is set at 20 mm; the saw-tooth roller speed should not surpass 525 r/min; the doffing roller speed must be greater than 350 r/min; and the screw conveyor auger speed is specified as 215 r/min. Following the theoretical design, a prototype was fabricated. A three-factor, three-level Box-Behnken experimental design was implemented to evaluate performance. The independent variables were machine forward speed, pickup roller speed, and saw-tooth roller speed. The response variables were the residual cotton pickup rate and the impurity content rate. Mathematical regression models describing the relationship between the factors and responses were established. Multi-objective optimisation was subsequently performed using Design-Expert 10.0.4 software. The key findings are: 1) The optimal parameter combination for the device was determined as: a forward speed of 0.70 m/s, a pickup roller speed of 251.31 r/min, and a saw-tooth roller speed of 249.31 r/min. Under these theoretically optimal conditions, the predicted residual cotton pickup rate is 90.22% with an impurity content rate of 18.27%. 2) Analysis of factor significance revealed that the order of influence on the pickup rate is: pickup roller speed, forward speed, saw-tooth roller speed. Conversely, the order of influence on the impurity content rate is: forward speed, pickup roller speed, saw-tooth roller speed. 3) Investigation of factor interaction effects provided further insights. An excessively high forward speed leads to missed pickup, reducing the collection rate, while a very low speed compromises operational efficiency and accelerates component wear. Increasing the pickup roller speed assists in detaching seed cotton from the ground and stalks, facilitating conveyance. However, an overly high speed can cause seed cotton to be flung away or torn, adversely affecting both the pickup rate and the quality of the recovered material. An insufficient pickup roller speed hinders effective collection and ejection. A higher forward speed increases the material throughput of the saw-tooth cleaner, potentially leading to inadequate cleaning and thus a higher impurity content. A slower speed reduces throughput but improves cleaning effectiveness, lowering impurity levels. Furthermore, an excessively high pickup roller speed subjects the cotton to greater impact during pickup, which can reintroduce separated impurities back into the fibre mass. An inadequately low speed fails to separate impurities effectively, both scenarios resulting in elevated impurity content. A final validation test was conducted using practical, rounded parameter values based on the optimisation results: a forward speed of 0.7 m/s, a pickup roller speed of 250 r/min, and a saw-tooth roller speed of 250 r/min. The average measured pickup rate was 89.53% (a decrease of 0.69 percentage points from the predicted optimum), and the average impurity content rate was 18.91% (an increase of 0.64 percentage points). These deviations fall within an acceptable error margin, confirming the reliability of the optimisation model and demonstrating that the device's performance meets core agronomic requirements. In conclusion, this research provides a valuable reference for the development of mechanised technologies and equipment for residual cotton recovery. Moreover, it offers novel theoretical and practical insights applicable to the pickup of irregular, clumped, flexible materials in general.