A simple and practical method to measure the load of AGV(automated guided vehicle), which calculated the additional torque of the load through measuring longitudinal obliquity of AGV, was adopted. Dynamic theoretical analysis and mathematical model on a two-wheel-driven AGV have been completed. By experimental researches in working place, the compensation coefficient and the relationship between orientation angle and additional torque were obtained. The test results showed that trace tracking errors of AGV brought by longitudinal unsymmetrical loads could be eliminated to some extent by using this method. 