Abstract: To determine a better way to use sodium chromate solution to remove UV-A and UV-C from UV-B light source,ultraviolet absorption characteristics of sodium chromate at different concentrations and pH levels were studied.The physiological activities and biochemical component of Nostoc commune under UV-B light source with and without filtration by sodium chromate were also studied.Results showed that sodium chromate works well to remove UV-C and UV-A at a concentration of 0.4 mmol/L and pH 8.Compared with filtered UV-B light source,the unfiltered UV-B light source inhibited the growth,chlorophyll synthesis,F_v/F_m,maximized photosynthetic rate and light harvesting efficiency of N.commune significantly.However,it also promoted the synthesis of ultraviolet absorbed material such as MAAs in the cells of N.commune.Compared with N.commune grown without UV-B radiation,N.commune grown with filtered UV-B light source had lower F_v/F_m,maximized photosynthetic rate and light harvesting efficiency but higher content of MAAs.But there was no significant difference between their growth.