This study is to study the improvement effects of herbaceous plant (Cynodon dactylon) planting on the clayey coastal saline-alkali land. The coastal saline-alkali soil with and without Cynodon dactylon planting in Lianyungang City of Jiangsu Province was taken as the experimental object, soil samples of Cynodon dactylon planted for one year and the bare land (CK) were collected and determined. The results showed that Cynodon dactylon planting reduced soil salinity, pH value, and the concentrations of Ca²⁺, K⁺, Mg²⁺, Na⁺ and Cl^-, increased soil moisture, the contents of organic matter, available phosphorus, the diversity and richness of soil microbial community. In conclusion, the cultivation of Cynodon dactylon has the remarkable effects on the removal of saline-alkali barrier and the improvement of soil fertility in the clayey coastal saline-alkali land.