Abstract: There is a large area of saline alkali soil in our country’s coastal region, and saline alkali soil has unique physical and chemical properties and microbial flora. The saline alkali soil in Tianjin coastal area was taken as the object in this article, and the pH, the salinity, the organism content and the quantitative characteristics of microorganism of the soil were analyzed and the dominant species was also isolated and identified. The results showed that: The degree of soil salinity is distributed with speckle and lower fertility; The quantity of microbe in the soil changed in the range of 0.75×105—14.19×105 cfu/g, and bacteria were absolutely dominated; The higher salinity in soil, the less microorganism quantity, its relation equation was y=-3.759 8lnx+11.281. The amount of microbe were all in line with salt soil > high degree>middle degree>light degree, it has fully reflected the soil environmental condition synthesis influence as the leading factor of soil harm; With isolated and identified, the most of bacteria were Lactobacilli and Bacilli, and the most of actinomycetes were Streptomycete, and the most of fungi were Penicillium. The discovery of Halotolerant domesticated has the important theory and the practical significance to study the salinealkali soil in our country’s coastal region and to develop salinealkali soil specialpurpose fertilizer.