Abstract: 【Objective】The effect of nitrogen on chlorophyll and photosynthesis of perilla frutescens under drought stress was preliminarily determine.【Method】The effects of nitrogen application on the chlorophyll content and photosynthetic index of different varieties of perilla frutescens under different drought stress were studied by pot experiment. 【Result】The results showed that the chlorophyll content, photosynthetic rate, transpiration rate, stomatal conductance and intercellular CO2 concentration differed significantly under various drought stress conditions. The chlorophyll content were increased with the increase of N application. With N application amount of more than 300 kg/hm2 under mild drought stress treatment, chlorophyll content of TD-S-1 presented a downward trend, and that of LS-Y-1 continued to rise. TD-S-1 and LS-Y-1 had the highest photosynthetic rate when the nitrogen application amount was 300 kg/hm2 under mild drought stress, which was 1.39 times and 1.29 times higher than that without nitrogen application, respectively. The change trend of stomatal conductance and transpiration rate was consistent with that of photosynthetic rate, and the intercellular CO2 concentration was the lowest. 【Conclusion】It can be concluded that under mild drought stress, nitrogen application of 300 kg/hm2 has a certain promoting effect on improving photosynthesis of perilla frutescens.