[Objective] The present paper aimed to explore the photosynthesis-related cold-resistant genes in Mandragora chinghaiensis grown at high altitude and low temperature. [Method] Taking 0 °C low temperature stress Qinghai eggplant ginseng as the experimental material, the key time points were found through photosynthetic physiological experiments, and then transcriptomics analysis was carried out to screen photosynthetic related cold-resistant genes and perform real-time fluorescence quantitative analysis. [Result] The net photosynthetic rate, stomatal conductance, transpiration rate, maximum fluorescence, maximum photochemical efficiency of photosystem II, photochemical quenching coefficient, and electron transfer rate showed a gradual downward trend, while the intercellular CO2 concentration, initial fluorescence, and non-photochemical quenching coefficient showed an upward trend. Based on the comprehensive analysis of changes in photosynthetic and chlorophyll fluorescence parameters, the key time node was 12 hours. According to the analysis of transcriptome, seven genes were screened. Through qRT-PCR analysis, the expression of CP43 gene was up-regulated first and then down-regulated, showing an overall upward trend; The expression of CAB-8, САВ-11, СР24-10B, CH-02, FD-C2, and PSI-D2 genes was first down-regulated and then up-regulated, showing an overall downward trend. [Conclusion] The results of the study provided some theoretical support for the screening of photosynthesis-related cold resistance genes and the subsequent transgenic verification, the main purpose of screening genes has been achieved. [ABSTRACT FROM AUTHOR]