In order to explore the effects of organic materials on the saline-alkaline soil physicochemical and biological properties，the experiment was continuously conducted in the saline-alkaline environment of Hailiutu site of Inner Mongolia Agricultural University from 2016 to 2018.The changes of soil pH，electrical conductivity，the contents of soil microbial biomass carbon，nitrogen，phosphorus，soil enzyme activities，and oat yields were investigated under four treatments:negative control(CK)，bio-fertilizer(F)，decomposed straw(S)，and decomposed straw combined with bio-fertilizer(FS).The results showed that F，S and FS treatments significantly decreased soil pH in 0～5，5～10，10～20 and 20～40 cm soil layers，as well as significantly increased the contents of soil microbial biomass carbon，nitrogen，phosphorus，and soil enzyme activities of sucrase，urease and alkaline phosphatase in 2016，2017 and 2018，and FS treatment performed best，but it caused higher soil conductivity.Compared with the control，the grain yield，fresh grass yield and dry grass yield increased by 121.48%，65.97% and 48.22% in 2016，and increased by 146.06%，102.13% and 77.23% in 2017，and increased by 36.55%，23.53% and 43.20% in 2018，respectively；In 2016 and 2017，the economic benefits of oats improved.In addition，when organic materials were continuously positioning applied to the saline-alkali land，oat grain yield was directly and indirectly affected by soil physical，chemical and biological properties in 2016，2017 and 2018.