Abstract: To assess the response of microbial community to salinity and soil moisture by denaturing gradient gel electrophoresis （DGGE） and phospholipid fatty acids （PLFA） analysis， we carried out an incubation experiment under different salinity and soil moisture gradients by adding varying amounts of salt and water to a coastal saline soil. Treatments included a concentration of four salinity levels: 1.90， 9.41， 19.76 and 26.92 g NaCl·kg-1 soil， corresponding to an electrical conductivity of 0.68， 3.55， 7.49 and 10.22 dS·m-1 and three moisture contents: 20%， 30% and 40%. The results showed that soil moisture did not significantly affect soil bacterial and fungal diversity， but soil salinity significantly decreased soil bacterial and fungal diversity. The bacterial and fungal diversity indices and richness indices in the soil salinity treatments of 19.76 and 26.92 g NaCl·kg-1 soil were lower than those in the other two treatments， of which the lowest diversity index and richness index appeared in the treatment with soil salinity of 26.92 g NaCl·kg-1 soil and soil moisture content of 40%. Soil moisture did not significantly affect bacterial biomass， but significantly reduced fungal biomass. The fungal biomass in the soil moisture treatment of 20% was significantly higher than those in the soil moisture treatments of 30% and 40%.

Key words: coastal saline soil, soil moisture, salinity, DGGE, PLFA