Abstract: The rapid dissipation of heat generated by light-emitting diode (LED) sources is critical to ensuring their performance, operational longevity, and reliability in plant factory environments. Dry ice jet cooling presents a dual-function solution by efficiently extracting heat from LED modules while simultaneously supplying sublimated carbon dioxide (CO₂) for crop carbon supplementation. This study designed and evaluated an integrated system combining dry ice jet cooling with CO₂ enrichment, investigating the effects of varying fluid inlet velocities on LED heat dissipation and the subsequent impact of carbon supplementation on lettuce growth parameters. Under a constant input power of 100 W, the thermal performance of the LED module was assessed at dry ice fluid inlet velocities ranging from 0.005 to 0.007 m/s. Results demonstrated that within this velocity range, the surface temperature of the LED module remained consistently below 60 ℃ with uniform distribution across the surface. Compared to conventional water cooling methods, dry ice jet cooling achieved a reduction of approximately 10 ℃ in the central region temperature of the LED light source, indicating superior localized heat dissipation efficiency. The CO₂ released during dry ice sublimation was utilized for carbon enrichment in lettuce cultivation. Morphological and physiological analyses revealed substantial improvements across multiple growth indicators following carbon supplementation. Average plant height increased by 4 cm, stem diameter by 1.6 mm, and leaf number by three leaves per plant. Biomass accumulation was significantly enhanced, with fresh weight per plant increasing by 132.87 g and dry weight by 11.21 g. Biochemical assays further demonstrated elevated pigment concentrations, including chlorophyll a (0.2 mg/g), chlorophyll b (0.052 mg/g), and carotenoid content (0.057 mg/g). Nutritional quality parameters also showed marked improvements, with soluble protein content rising by 1.39 mg/g, vitamin C content by 49.99 µg/g, and reducing sugar content by 7 mg/g. These findings confirm that carbon supplementation via dry ice sublimation effectively promotes lettuce growth and nutritional quality. Economic analysis compared the proposed system with conventional water cooling infrastructure. Results indicated that the dry ice-based system incurred lower equipment investment and operational costs, yielding a net economic benefit of 33.93 yuan per square meter per month. This cost advantage stems from the elimination of water circulation components and the value added through enhanced crop productivity and quality. This integrated approach addresses two critical challenges in artificial light plant factories: thermal management of high-intensity LED lighting and atmospheric carbon enrichment for optimized photosynthesis. By converting waste heat dissipation into a resource for crop production, the system embodies a circular economy principle. The study provides a foundational framework for implementing dry ice-based cooling and carbon supplementation strategies, contributing to the development of more energy-efficient and productive controlled-environment agriculture systems. Future research directions may include optimizing injection parameters for different crop species, scaling the system for commercial applications, and assessing long-term impacts on both LED lifespan and crop performance across multiple growth cycles.