The invention relates to cytochrome P450, specifically to a method for measuring the content of a biomarker-cytochrome P450 in earthworm viscera, which comprises the following steps of: (1) soaking a live earthworm in glycerol solution, and immediately dissecting and taking out the viscera thereof; (2) cleaning the viscera with cold saline water, transferring to a homogenization buffer, breaking cells with a glass tissue grinder, centrifuging with a ultra-speed centrifuge at low temperature (3DEG C) and 10,000g for 20min, centrifuging the supernatant at 150,000g for 90min, removing the supernatant, and collecting microsome sediment; and (3) dissolving the microsome sediment in a storage buffer, mixing, and measuring the total amount of cytochrome P450 and the protein content in the microsome suspension. The total amount of cytochrome P450 is quantified with sodium hydrosulfite-reduced CO difference spectra method. The invention has the advantages of simplicity, rapidness, low consumption, and accurate qualification and quantitation.