In this study，the effects of microbial fertilizers on the soil secondary salinization and tomato production inprotected cultivation were studied through filed experiments in Taicang，Jiangsu.The results showed that the microbial biomass increased and the soil salt content decreased significantly in soil treated with microbial fertilizer comparing withnormal fertilizationtreatment，and the average increase of bacteria and actinomycetes reached 64.80% and 40.28%respectively.Inaddition，when the application rate of microbial fertilizer was 1.2 kg/m 2，the soil pH had the largest increase by 60.29% and the concentration of NO^3-decrease the most by96.18%.The contents of total salinity inT1，T2，T3，T4 decreased with0.76，1.49，1.54，1.87 g/kgrespectively.Soil quality and nutrient content were also improved bymicrobialfertilizers，amongthem，the bulk density decreased with 1.60%～ 11.20% and organic matter content increasedwith 4.81%～28.35%.And when the application rate of microbial fertilizer was 0.9 kg/m 2，the soil total nitrogen contenthad the largest increase by29.41%.However，the application of microbial fertilizers decreased the content of available phosphorus with 3.88%～29.85%.And microbial fertilizers also decreased the concentration of Cd in soil and when the application rate of microbial fertilizer was 1.2 kg/m2，the decrease was thelargest，which was76.09%.On the otherhand，microbial fertilizer also had a significant effect on tomatogrowth.Stemdiameter，leaf age and crown width increasedduring the growth period，and the promoting effects was particularly obvious with the microbial fertilizer application at 0.3 and 0.6 kg/m2.And microbial fertilizer also influenced the tomato yield andquality.When the application rate of microbial fertilizer was 0.9 kg/m2，both fruit amount and total weight were the highest among the different treatments and higherthan that in normal fertilization treatment with 42.86% and 36.36%respectively.As aresult，the application of microbialfertilizers could significantly improve soilconditions，reduce soil salt content and alleviate the secondary salinization ofthe soil，and thus increasing tomato yield and quality.Considering the effect of soil improvement and economic cost，thesuitable application rate of microbial fertilizer is 6 000～ 9 000 kg/hm².