Abstract: By analyzing the formation mechanism of reinforced arch, we consider that the strength of reinforced arch is relative with its thickness, roadway span and anchorage rock strength, the form conditions of reinforced arch include bolt length, spacing and arching load. Based on the existing bolt reinforcement effect conclusions, we derived the relationship formula of the arching load between anchorage rock strength, then obtained the calculation formula of reinforced arch strength based on this conclusion. Through the parametric analysis, we obtained the influence laws of arching load, bolt length, bolt spacing and roadway size in reinforced arch's strength.