In order to achieve the transformation from the conventional soil-covering cultivation of Tricholoma giganteum with bags to the soilless cultivation with bottles and understand the mechanism of primordium formation of Tricholoma giganteum, with Tricholoma giganteum mycelia as experimental materials, this paper studied the effect of different fruiting treatments on the activity of three enzymes in different time. The results showed that from the mycelial recovery to primardial formation and budding under three treatment groups which could form primordium, the tyrosinase activity was relatively stable, and under two treatment groups which could not form primordium, the tyrosinase activity dropped after the rise and reached a maximum on the 9th day, significantly higher than under the other three groups, indicating that too high tyrosinase inhibited primardial formation; the prolease and amylase activity was effectively activated before primardial formation, and the enzymic activity was significantly higher than under the two treatment groups which could not form primordium.