Soil salinization causes the deterioration of soil environment，and limits the effective use of nitrogen by crops. Controlling the soil salinization process is important for the development of agricultural productivity. The objective of this study was to evaluate the effects of plastic film mulch and straw return on the soil saline-alkali properties and crop nitrogen utilization in coastal salinized farmland. Pot experiments were conducted in the greenhouse of Yangtze University from December 2020 to June 2021. The experiments contained five treatments:film mulch(FM)，straw return(SR)，film mulching plus straw return(FM+SR)，no film mulch and straw return，only fertilizer(CK)， no film mulch and straw return，no nitrogen fertilizer(CK0). Soil samples were collected after barley harvest. Meanwhile，the barley plants were collected manually from each pot. The soil salt content，pH，moisture content，bulk density and aggregate，barley yield and nitrogen content were analyzed，the nitrogen uptake and nitrogen use efficiency were calculated. Results showed that(1)Single or coupled application of film mulch and straw return significantly reduced soil salt content，of which，FM+SR treatment showed the most significant effect，with the soil salinity decreased by 37.53%. However，their effects on soil pH were not significant. (2)The effect of single or coupled application of film mulch and straw return on soil bulk density was not significent. FM+SR treatment improved the content of soil water-stable macroaggregates (>0.25 mm)，as well，the soil moisture content in the topsoil improved by treatment 10.18%. (3)FM+SR treatment had the highest yield and straw amount，which was increased by 17.98% and 13.10% respectively，compared with CK. In terms of nitrogen uptake，the nitrogen uptake in FM+SR treatment was also the highest，which increased by 17.88%. (4)FM+SR treatment also significantly increased the nitrogen recovery rate，nitrogen agronomic efficiency and nitrogen partial productivity，the increases were 25.45%，32.45% and 17.98%，respectively，while reducing the apparent nitrogen loss. In conclusion，FM+SR treatment reduced the soil salinization mainly by improving the soil water and salt transport process in salinized farmland，meanwhile，it had significant impact on the improvement of soil aggregate structure and moisture content. Finally，the yield，nitrogen uptake and nitrogen nutrient utilization efficiency were improved in FM+SR treatment.