Abstract: Abstract: L7 as experimental material is hybrid strains of Flammulina velutipes. The native—PAGE analysis showed that it possessed three kinds of laccase isoenzymes. By using spectrophotometry and choosing ABTS[2,2’—Azino-bis(3一ethy lbenzothia— z0line一6—sulfonicacid)]，the activity of laccase can be determined, the results show that: the appropriate determination of a wavelength 410 nm,system pH4.5, reaction temperature 45℃.