A method for judging abnormal loading of vehicles includes the steps of: receive a plurality of tire pressures (P) generated by a tire pressure detection unit (111) during a plurality of inspection time periods (T) and calculate variation amount of the tire pressures (P) and convert to a gradient data (M1) judge whether the gradient data (M1) is positive in value, if positive, calculate the tire pressure (P) obtained at the last time and tire parameters via a tire sinking amount calculation formula to get a tire deformation amount (f), and calculate the tire pressure (P) obtained at the last time and the tire parameters via a loading calculation formula to get a tire loading data and compare the tire loading data and the tire deformation amount (f) via a tire abnormal condition judge the vehicle (1) in abnormal loading if the tire loading data and the tire deformation amount (f) coincide with the tire abnormal condition. Fig. 3
