The invention relates to a phytase microbial inoculum which comprises a Bacillus Lip-3 strain and a fermentation culture medium, wherein the concentration of the Bacillus Lip-3 strain is 2-10*10<8>/mL; and the fermentation culture medium comprises the following components in percentage: 0.3-0.5% of beef extract, 0.5-1.5% of peptone and 0.4-0.6% of NaCl. The phytase microbial inoculum can promote the plant growth, increase the crop yield and improve the quality. The phytase microbial inoculum can be used for the cultivation of various vegetables, melons and fruits in agricultural greenhouses, such as cucumbers, tomatoes, pakchoi, kidney beans, aubergines, romaine lettuces, leaf lettuces, towel gourds, peppers, rape, sweet melons, strawberries, grapes and the like; the phytase microbial inoculum can be used for field crops, such as corn, wheat, soybeans, sugarcanes and the like; and the phytase microbial inoculum can be also used for fruit trees, such as peach trees, pear trees, jujube trees, apple trees and the like. Especially, the phytase microbial inoculum can promote the growth of Brassica chinensis L., can obviously increase the yield of cucumbers and tomatoes, and has considerable economic and social benefits.