Salt accumulation was found to have occurred in greenhouse soils in Haimen, making the salt content therein 3~4 times higher than in the neighboring open field soil. Salt content in the greenhouse fluctuates significantly within a year, rising up to 0.38~8.03 g/kg with an average of 3.28 g/kg during the greenhouse operating period (from October to May next year) and falling by 36.9%, down to 2.07 g/kg, during the open cultivation season (from May to October). Severe salt accumulation seldom occurs in the soil under periodical greenhouse cultivation within a year, which may be attributed to the special weather conditions of the region. Greenhouse salt accumulation can be effectively controlled with proper measures.