In order to effectively monitor and analyze the growth of fungi,this paper established a mathematical model to deal with it. First of all, we selected a Monte Carlo simulation model to simulate according to temperature and humidity to get its possible distribution. Secondly, on the basis of the previous model, we simulated the decomposition agents with different growth rates and different moisture resistance respectively, and finally got their relevant distribution. Third, we selected a grey prediction model to simulate the situation of different fungi separately, and got their specific distribution predictions. At the same time, it is described by the corresponding growth characteristics of different types of fungi, and their sensitivity is used to explain the impact of different weather. Finally, we established a principal component analysis model to analyze the data of different fungal communities, and estimate the growth of the fungi through temperature, humidity, etc., so as to clarify the biodiversity level of different fungal communities and give their impact.