The invention discloses a microbial liquid fungicide containing pantoea alhagi. The microbial liquid fungicide containing the pantoea alhagi comprises the following components in percentages by mass:1-10% of promoting growth bacteria fluid, 0.1-10% of polyglutamic acid, 50-70% of biological organic matters and the balance of water or aqueous solution. The promoting growth bacteria fluid comprisespantoea alhagi fluid. The invention further discloses a preparation method and application of the composite microbial liquid fungicide. The composite microbial liquid fungicide has a high-activity biological function, wherein the polyglutamic acid, the biological organic matters and a microbial agent have a synergistic effect, a microbiome environment of root systems of crops can be improved, thenumber of beneficial microorganisms in soil is increased, the quality of the crops can be improved, the yield is increased, and resistance against disadvantages such as drought resistance, salt resistance, cold resistance and disease resistance of the crops is enhanced.