In order to explore the impact of uranium on algae growth and photosynthesis, and screen new and based on photosynthetic ecological risk assessment indicators for uranium pollution in water bodies, this experiment used different concentrations of uranium (0, 0.5, 1, 5, 10, 20mg U·L-1) to treat two types of microalgae from different growth environments, Chlorella vulgaris and Huanglong Chlorella vulgaris. The relative growth rate, photosynthetic oxygen release rate, chlorophyll content, and chlorophyll fluorescence kinetic parameters were measured on the 3rd, 5th, 7th, 10th, and 14th days after treatment. The results showed that: (1) 0.5mg·L-1 low concentration uranium treatment significantly promoted the growth and photosynthetic efficiency of two types of microalgae, manifested as the relative growth rate, photosynthetic oxygen release rate, maximum photochemical quantum yield (Fv/Fm) of photosystem II, actual photochemical quantum yield Y (II), and relative electron transfer rate rETR of the two microalgae being significantly higher than the control, however, high concentration uranium treatment of 5-20 mg·L-1 significantly inhibited the growth and photosynthesis of two types of Chlorella. (2) Huanglong Chlorella vulgaris is more sensitive to uranium treatment than Chlorella vulgaris, and its growth and photosynthesis are significantly inhibited at a concentration of 1mg·L-1, and it can be used as an bioindicator for biological monitoring of uranium pollution in water bodies; (3) Regression analysis shows that under different concentrations of uranium treatment, the response speed of chlorophyll fluorescence parameters Y (II) and rETR is faster than the changes in relative growth rate, photosynthetic oxygen release rate, chlorophyll content, and Fv/Fm, which can be used as sensitive indicators for ecological risk assessment of uranium pollution in water bodies.