To investigate the effects of different fertilizer application patterns on the chemical properties，microbial diversity of coastal lightly saline soils，and on phenotype and yield of maize，and to determine the appropriate improvement pattern for coastal lightly saline arable land，five fertilizer patterns were tested through maize field trials:conventional fertilization(T1)，optimized fertilization(T2)，optimized fertilization + organic fertilizer(T3)，optimized fertilization + functional fertilizer(T4)，and optimized fertilization + microalgae fertilizer(T5). Soil chemical properties and microorganisms were measured before sowing and after fertilizer application，and maize dry matter accumulation and yield were measured at maturity. The results showed that the total nitrogen content of T3 was significantly higher by 40.80% compared to that of T1；The pH of T4 was significantly lower than that of T1 by 7.27% and the organic matter content was significantly higher than that of T1 by 13.53%；the salt ion concentration of T5 was significantly lower than that of T1 by 5.61%. Among the five fertilization patterns，T3 and T4 had higher levels of saline-friendly flora such as Actinobacteria，Proteobacteria and Chloroflexi，with T3 having the highest microbial community diversity index and T2 having the highest microbial community abundance. Dry matter accumulation increased by 9.21% and 3.31% in T3 and T4，respectively，and maize yield increased by 20.51% and 12.23% in T3 and T5，respectively，compared to T1. Considering the combination of yield and soil improvement，T3 is the optimal improvement pattern suitable for mild coastal saline soils in Luannan county and has a significant improvement effect on mild coastal saline soils of maize.