Abstract: IP.this paper were investigated soil fertility factors,such as the quantity of microorganisms,the biochemical and enzymatic activities and the nutrient in the mixed forest of Picus massoniman and Caslanopsis fissa of Zengeheng Forest Farm,Guangdong Province.Among the 18 fertility factors investigated the annual average of 14 factors in the mixed forest is higher than those in pure forest of P.massoniaus.This shows that the mixed forest gets obviously higher fertility level of soil than the pure forest does.Comparing the mixed forest with the pure forest,the seasonal quantity and activities of microorganisms in soil are nearly equal to each other,but the nutrient and the enzymatic activities very differ.