Abstract: The spectrophotometric method in different conditions of light and temperature, extraction of phytoplankton chlorophyll a determined, to study the different illumination and temperature on the extraction of phytoplankton chlorophyll a and determine phytoplankton chlorophyll a in the optimum conditions of extraction. Strictly avoid light in the filtration process, and use the ice water mixture is cooled to 0 ℃ preservation, water filtration. Leaching provided to avoid light（less than 200 lx refrigerated（-1-1 ℃）group, light（1 100-1 700 lx）cold（-1-1 ℃）group, evades the light（less than 200 lx）at room temperature（26-30 ℃）group and light（1 100-1 700 lx）at room temperature（26-30 ℃）group, each group into the 90% acetone solution extraction 19 h. The average extraction amounts of the four groups were as follows: 155.73 μg/L of the cold storage group and 136.24 μg/L in the light cold storage group, 116.67 μg/L in the ambient temperature group and 89.85 μg/L in the normal temperature group. The results showed that the optimal extraction conditions of phytoplankton chlorophyll a were cold storage and light avoidance.

Key words: chlorophyll a, extraction, temperature, illumination