In order to investigate the influence of photosynthesis on rice flag under enhanced UV-B radiation and He-Ne laser. He-Ne laser (5 mW·mm-2) irradiation and enhanced UV-B (13.08 kJ·m-2·d-1) radiation were used, the chlorophyll content and Rubisco of rice seedling leaves, chlorophyll fluorescence parameters about plant photosystem II (PSII) are measured. The results show that, after UV-B treatment, the chlorophyll content in rice leaves, and fluorescence parameters (other than qN) is lower than the control group (CK) and has significant differences (P<0.05). The fluorescence parameter photochemical quantum yield (Fv/Fm) is the most sensitive to environmental stress reflection. In indicator group treated by He-Ne laser (L), the chlorophyll content and Rubisco in rice leaves are higher than the control group (CK) (P>0.05), fluorescence parameters does not change significantly (P>0.05). Compared with the control group (P<0.05), groups treated with He-Ne laser and UV-B, chlorophyll content, rubisco, and fluorescence parameters (except for qN ) of the rice leaves are higher than UV-B treated group. UV-B radiation on rice seedlings has injury to PSII, and a certain dose of He-Ne laser can improve the photosynthetic efficiency of rice. He-Ne laser can repair damage of enhanced UV-B to rice.