The invention relates to a coated granular microbial agent and a production method thereof. The coated granular microbial agent is prepared by the following raw materials by weight percent in a mixing way: 7-20 percent of a microbial liquid, 50-85 percent of an adsorption carrier, 0-40 percent of a binding agent and 1-10 percent of a coating agent. The production method comprises the following steps: firstly weighing the raw materials with corresponding percent, mixing the adsorption carrier with the binding agent, adding the microbial liquid to adsorb and then crushing, performing granulation on the crushed material, drying the material after granulation and screening to obtain the finished product granular material through a screening machine, performing aeration-cooling on the finished product granular material and conveying the material after cooling to a coating machine and adding the coating agent for coating, and performing aeration-cooling and drying on the material after coating. The coated granular microbial agent has the benefits of no chemical reaction, no air slaking, no crushing for granules, no formation like sticky mud, good fluidity, high strength, soil adjustment, soil improvement and fertilizer effect enhancement when being mixed with chemical fertilizers such as urea, compound fertilizer and the like for use, and reduces the use cost.