The invention relates to a method for preparing microgel through enzymatic polymerization, which comprises the following steps: taking normal octane and acetylacetone, uniformly mixing, adding an emulsifier, fully mixing to prepare an oil phase, introducing argon to remove oxygen, taking a certain amount of N,N-dimethylacrylamide, successively adding N,N-methylene bisacrylamide and deionized water, performing ultrasonic mixing, after N,N-methylene bisacrylamide is completely dissolved, adding horseradish peroxidase and uniformly stirring to prepare a water phase solution; dropping the water phase solution in the oil phase, uniformly stirring to prepare an anti-phase emulsion; adding hydrogen peroxide in the anti-phase emulsion, continuously introducing argon for a polymerization; after polymerization is completed, adding excessive ethanol for demulsification, centrifuging, taking sediment at bottom, and washing to obtain the semi-clarity yellow-brown microgel. Compared with prior art, the preparation condition of the method is mild, the process is simple, the obtained microgel has the advantages of structured shape, smooth surface and narrow particle size distribution.