The invention provides a liquid organic microbial fertilizer. The liquid organic microbial fertilizer comprises a chelate containing mixture, a microbial agent and a pH regulator, a weight ratio of the chelate containing mixture, the microbial agent to the pH regulator is 19-41:5-15:0.5-2, and a pH value of the liquid organic microbial fertilizer is 5.5-6.5. The chelate containing mixture comprises medium-trace-element salt and fermentation waste liquid, and a weight ratio of the medium-trace-element salt to the fermentation waste liquid is 4-11:15-30. The liquid organic microbial fertilizer which takes the fermentation waste liquid as a culture carrier is low in cost, raw materials are safe and free of contamination, microbial survival rate is high, and the shelf life of the fertilizer can be prolonged. In addition, the liquid organic microbial fertilizer has the advantages of nutrition comprehensiveness, high viable count, long shelf life, stable fertilizer efficiency and high environment friendliness.