Abstract:Monthly changes in number of bacteria, filamentous fungi and actinomycetes in the layers of litter, decay and top soil (at 0 - 20 cm depth) of Hexi subtropical rain forest in Fujian Province were studied in 1989. The results showed that dricrobial number in all the three layers was great for bacteria, and less in descending order for filamentous fungi, and actinomycetes. Microbes found in litter and decay 1ayers were more than those in the top soil layer. Distinctive seasonal change in quantity of each microbial group and a similar pattern of monthly dynamics were observed. There was a peak of microbial increasing during the year, in April for bacteria, in May for fungi, and in August for actinomycetes. The number of bacteria and filamentous fungi in each layer was positively correlated with the month1y litter fall, precipitation and mean temperature (p <0.01 or 0.05), while the number of actinomycetes was correlated only with monthly mean temperature.