Abstract: The conidia of Beauveria bassiana is the key factor of the fungal insecticides used most widely. To know the effects of different media and culture times on the stress resistance of B. bassiana conidia. Five strains with fast growth and high spore production from 30 strains collected from different temperature zones in China（RCEF5609, RCEF5746, RCEF5688, RCEF6200 and RCEF6857） were selected. The heat resistance and UV resistance of strains were studied by using commonly used culture media with different nutritional richness degrees in the laboratory（PDA, SDAY and MEA） and different cultivation times, and the changes in transcription levels of related genes were analyzed. The results showed that the germination rate of conidia of strains RCEF6200 and RCEF5688 was the highest and with the strongest stress resistance, while RCEF5609 had the lowest germination rate and the weakest stress resistance. It was shown that the conidia produced by poor nutrient culture medium PDA were stronger tolerance for heat resistance and UV resistance than those produced by rich nutrient SDAY and MEA, and the conidia cultured for 7 d had stronger stress resistance. Further analysis of the transcription levels of stress resistant genes in the strongest stress resistant strain RCEF6200 and the weakest stress resistant strain RCEF5609 showed that compared with the control group, the expression levels of heat resistance and UV resistance related genes in the strains RCEF6200 and RCEF5609 increased to varying degrees on PDA medium and under 7 d of cultivation conditions compared to other treatments.The transcriptional analysis results of stress resistance related genes further confirmed the above results. A theoretical basis for the production of strong stress resistant fungicide of B. bassiana was provided.