The invention discloses a polyacrylamide/microsphere composite gel and a preparation method of the polyacrylamide/microsphere composite gel. The polyacrylamide/microsphere composite gel is formed by crosslinking polyacrylamide and a polymeric microsphere; the polymeric microsphere is an acrylamide/hydroxyethyl methylacrylate composite microsphere; and the mass ratio of the polyacrylamide to the polymeric microsphere is 2:(1-10). As the conventional polymer gel is in a three-dimensional hole network structure, the main ingredient of the conventional polymer gel is water molecule, the chain structure of the gel is loose, and the gel is relatively low in strength, has certain mobility, and cannot reach the required strength of a gel valve in the application of an oil field. Particularly for the high-pressure stratum, the conventional gel cannot effectively prevent the oil gas from overflowing. Aiming at the situation, the organic microsphere is added in the polymer gel to reach the effectof improving the strength, so that the mechanical strength of the gel valve is improved, and the property of the gel valve in a sleeve is improved. The interaction between the organic microsphere andthe polymer is also investigated, and the polyacrylamide/microsphere composite gel has a guiding significance for improving the mechanical property of the gel valve.