The effects of selenium enriched microorganisms on the nutrient，selenium content and form of organic fertilizer in the composting process were explored to provide a theoretical basis for the practice of the resource utilization of agricultural waste to produce selenium rich agricultural products. The composting experiment was conducted by mixing mushroom residue，rapeseed meal and straw. The control group(CK)，EM (effective microorganisms) group(T1)，selenium-riched Bacillus subtilis group(T2)and selenium-riched Azotobacter chroococcum + selenium-riched Bacillus subtilis group(T3)treatments were set up. The composting effect of different selenium rich microorganisms were studied，the nutrient and selenium content of the organic fertilizer were analyzed，and the application effect of selenium rich fertilizer on spinach planting was verified. The results showed that after 38 days of composting，the composting test all met the agricultural standard of “Organic Fertilizer”(NY/T 525-2021). Compared with CK，the total nutrient content of T3 treatment was increased by 13.70%，the total nitrogen content was increased by 26.06%，the decomposition ability of organic matter was increased by 4.88%，total selenium(calculated by pure Se)was increased by 1.93 times，and the occurrence form of selenium in organic fertilizer was changed. Pot experiment showed that the plant height，root length，leaf width，fresh weight and chlorophyll content of spinach in F1(manuring T1 organic fertilizer)，F2(manuring T2 organic fertilizer) and F3(manuring T3 organic fertilizer) were significantly higher than those in OF(manuring CK organic fertilizer)，and the total selenium content in spinach in F3 treatment was 126.72 μg·kg-1，which reached the highest content in the test，and was 3.27 times higher than that of OF. In a word，the composting effect of the selenium enriched composite microorganism combination in T3 treatment is the best，which is an ideal selenium enriched way for the development of selenium enriched functional agriculture in the engineering application of waste compost.