The invention relates to a preparation method of a liquid 
fertilizer containing microorganisms. The preparation method comprises: adding 
plant residues, an acid-alkali adjusting agent, 
distilled water, a culture medium and microorganisms into a 
fermentation tank, fermenting at a certain temperature, carrying out pH value adjustment and cooling on the product after fermenting for a certain time, storing for 3-5 days in the 
fermentation tank, adding slaked 
lime, adjusting the pH value, continuously adding the culture medium and the beneficial 
microorganism to the 
fermentation tank, fermenting at a certain temperature, carrying out pH value adjustment and cooling on the product after the fermenting, storing for 3-5 days in the fermentation tank, repeating the steps one time, carrying out press 
filtration on the product to obtain filtrate, and adding the filtrate to a liquid 
fertilizer to obtain the liquid 
fertilizer containing the microorganisms. According to the present invention, the natural 
ecological environment of the soil is simulated, and the three fermentations are performed, such that the fermented 
microbial agent can quickly adapt to the environment after being put into the soil so as to ensure the 
survival rate.