Preparation method of complex microbial inoculant for promoting plant growth

The invention discloses a preparation method of a complex microbial inoculant for promoting plant growth, which comprises the following steps: uniformly mixing 10-20 parts of bacillus megatherium and 10-20 parts of azospirillum to obtain a microbial inoculant body for later use; 5-10 parts by mass of a sucrose aqueous solution with the mass fraction of 2%, 1-3 parts by mass of agar, 2-5 parts by mass of peptone and 1-4 parts by mass of beef extract are stirred and mixed to obtain a culture medium, and the microbial inoculum body in the first step is added into the culture medium to be cultured at the culture temperature of 42-45 DEG C for 1-2 h for standby application. According to the complex microbial inoculant disclosed by the invention, the microbial inoculant body is cultured by a culture medium to form active complex thalli, and the active complex thalli are coordinated, modified, co-synergistically matched and loaded with the zeolite regulating modifier and the biomass charcoal regulator, so that the c