Abstract: The investigations of microbial flora of Spartina salt marshes, Yancheng, Jiangsu Province were carried out during October 2004 and August 2005, which aims to reveal the influence of introduction of Spartina on the microbial flora of salt marshes. The sampling sites were divided into Suaeda salsa land, Spartina land and beach according to the vegetation. The microorganisms were isolated and counted with pour plate technique. The results indicate that the amount of bacteria is bigger than actinomycetes, and the amount of fungi is least. From the point of spatial distribution, the amount of microbes in Spartina land is ＞Suaeda salsa land＞beach for bacteria, Spartina land≥Suaeda salsa land＞beach for fungi and Suaeda salsa land＞Spartina land＞beach for actinomycetes. From the point of temporal distribution, the amount of microbes is largest at August. Vegetation type, soil characteristics, content of organic matter, temperature and humidity of environments play important roles on the microbial distribution in salt marshes.