Bioremediation, a rising environmental biotechnology, increasingly plays an important role in controlling the pollution in soil, surface water and ground water. It has many merits such as low cost, good cleanup effect and no secondary pollution compared with the traditional physical and chemical remediation techniques. Cultivating with saline-enduring and saline-avoiding plants can effectively improve saline soil. The improvement effects ought to be studied not only on the physical and chemical properties but also on the biological characters. Bioremediation of coastal saline soil was carried out by planting halophyte Suaeda salsa L in Tianjin estuarine area. The effects on the soil microflora were studied by comparing the content of soluble salt, the microbial amount and the transition of dominant microflora in soil. The results showed that the content of soluble salt in S. salsa planted soil decreased by 41%(method of weight) and 37%(method of electric conductivity) compared with that of control respectively. It revealed that the halophyte S． salsa was salt-absorbing plant for saline soil. The results also showed that the microbial amounts were increased with the decrease of the soluble salt in the soil around S. salsa L. root system. The bacteria, actinomycete and fugi were increased 2.3 times, 4.3 times and 71 times respectively. The salinity for optimal growth of bacteria decreased synchronously with the decrease of salinity in the soil of root system. The bacteria with the lower ability of salt-tolerance have been becoming the dominant flora. The phylogenetic analysis based on the 16S rDNA indicated that the planting of S． salsa L also had effects on the sorts of bacteria in soil. Bacillus sp. became the dominant flora in saline soil after bioremediation by S. salsa. All these results demonstrated the remarkable improvement effect of ecosystem after S. salsa planting on coastal saline soil.