Based on the water infiltration experiments of sandy loam and clay loam soil, we determined the coefficients of entropy equations (E-Horton, E-Kostiakov, E-Philip, E-Green-Ampt) and general equations (Horton, Kostiakov, Philip, Green-Ampt). Infiltration rates were calculated from these equations, and compared with the data obtained by experimental observations. The results showed that E-Horton, E-Kostiakov, and E-Philip equations were suitable to fit soil water infiltration rates, and that E-Green-Ampt equation over-estimated soil water infiltration rates in sandy loam soil. However, these entropy equations were not suitable to fit infiltration rates in clay loam soil. Compared with the general equations, the entropy equations were more suitable to study infiltration rates in sandy loam soil. Since the entropy equations do not need any calibration parameters, they are feasible to reflect the physical meaning of the parameters and provide a theoretical basis for the optimization of irrigation.