Abstract: In order to select the improvement measures with better effect on saline-alkali land,by planting oats,using straw returned with different microbial fertilizer level to improve it.And study on the physicochemical and biological properties of soil affected by eight treatments that they were traditional management（A）,straw decayed returned（AF）,plus 750 kg/hm^2 microbial fertilizer（B）,straw decayed returned and plus 750 kg/hm^2 microbial fertilizer（BF）,plus 1 500 kg/hm^2 microbial fertilizer（C）,straw decayed returned and plus 1 500 kg/hm^2 microbial fertilizer（CF）,plus 2 250 kg/hm^2 microbial fertilizer（D） and straw decayed returned and plus 2 250 kg/hm^2 microbial fertilizer（DF）.And to further explore the improvement mechanism.By Correlation analysis for soil index of oat in the heading stage and filling stage,It was found that soil water content had significant or extremely significant positive correlation with the SMB-N,catalase,Alkaline phosphatase（ALP）enzymes of soil;And that SMB-C,SMB-N,urease,sucrase enzymes there were significant or extremely significant positive correlation between each other.The results showed that：Both the straw returned and researches two kinds of measures can improve the soil properties to some degree.The treatment of CF had obvious improvement effect.It＇s soil water content was higher,can significantly（P0.05） enhance content of SMB-C,SMB-N and activities of sucrase,urease,catalase and ALP.Combining with straw,the best applying content of microbial fertilizer was 1 500 kg/hm^2,this way that can be used as the best measures to improve the saline-alkali land.