To analyze the influence of the deformation of a vehicular platform on the angle measurement precision of a theodolite, a new method was presented to measure the deformation of the vehicle platform by using a inclinometer.Based on the principle of platform deformation dependent on measuring results, the inclinometer was put on the center of the vertical axis to get deformation angles of the center of working platform, then to calculate the measuring coordinate deflection and figure out the expressions on the output data of the inclinometer and angle measurement errors.A double-axis inclinometer was chosen to measure the deformation of the vehicle platform in real time.Experimental data show that the deformation sufferring from an azimuth axis velocity is small and the reading results after processing by a sliding weighted mean digital filter are 0 and 5.1″ for the smallest discrepancy and the biggest one,respectively.However,the boresight location has larger influence on the deformation,and the smaller elevation angles are,the larger the reading results of inclinometer are.This test provides the theoretics for improving angle measurement precision of vehicular platforms of theodolites.