In order to clarify the remediation effect of different peats on coastal saline soil, indoor culture experiment was conducted with two kinds of modified peats. The alkali modified peat was close to the original peat in the infrared spectrum, while the acid modified peat produced a unique wave peak at 1 710 cm^-1. The alkali modified peat particles had the least protuberance under scanning electron microscope, showing a more uniform texture. The alkali modified peat increased soil aggregates, while the original pea promoted the contents of organic matter and alkali-hydrolyzed nitrogen better than the modified peat. Alkali-modified peat reduced soil pH significantly, but acid-modified peat increased soil pH. Alkali modified peat enhanced the activities of soil catalase, sucrase and cellulase, while acid modified peat reduced soil enzyme activities and original peat had no obvious effect. Soil pH, available phosphorus and available potassium were significantly correlated with soil enzyme activities (P<0.05). In conclusion, alkali modified peat has the best remediating effect on costal saline soil in reducing salinity, alkali, soil hardening but promoting nutrition and vitality.