The backfill is presented by Duncan-Chang hyperbolic model, the foundation is considered to be linear elastic and reinforced concrete culverts are considered as rigid bodies. Based on the conditions of force equilibrium and deformation harmony, the theoretical formulae of earth pressure on the culverts are derived and the main influence factors on vertical earth pressure on the reinforced concrete culverts are discussed. The results show that the coefficient, ratio of the average normal pressure acting on the roof of the culvert to the average free field pressure at the roof level, increases with the increases of modulus of elasticity of the foundation, the high-width ratio of the culverts and the angle of internal friction of backfill, and that it decreases with the increase of compressibility of the backfill, the coefficient increases first and then decreases as the buried depth increase. The coefficient is maximum when the depth of backfill equals the height of initial plane of equal settlement.