The vehicle mobile laser scanning (VMLS) system is a highly integrated multi-sensor measurement system. The accuracy of the VMLS system depends on the accuracy of not only the integrated sensor, but also the calibration of boresight parameters between the laser scanner and the integrated navigation system. Considering the convenience and effectiveness of the calibration method of the boresight parameters and the accuracy evaluation of the VMLS system, a calibrating method of the boresight parameters of the VMLS system based on the reference planar features constraint was proposed. The proposed method was based on the direct georeferencing of lidar measurements including the boresight parameters. The equation used the minimum distance deviation from laser footpoint to reference plane as the constraint. In addition, considering the correlation between rotation and offset amount of the boresight parameters, the stepwise solving method was composed to separate boresight angle and offset parameters. Finally, through the datum acquired from calibration field and check fields, the internal and external accuracy of VMLS system were evaluated. The experimental results show that the proposed method can effectively eliminate the influence of boresight errors. After calibration, the internal accuracy is 0.007 m and the external accuracy is 0.024 m.