Abstract: Airborne LiDAR system calibration estimates a set of parameters to represent biases of LiDAR system. Mounting biases of LiDAR system contain bore-sight angle between laser scanner frame and IMU frame and lever-arm offset between the IMU and laser scanner centers. Each time when LiDAR system is installed or removed within the aircraft, small changes in the mounting parameters may occur, therefore regular calibration of mounting parameters is required. Using the rigorous model of LiDAR direct geo-referencing, quantitative analysis of mounting parameters and their effect on laser footprint location accuracy is described. This paper introduced a rigorous self-calibration method for estimating mounting parameters of LiDAR system, namely the three bore-sight angles and the lever-arm offset. In order to model the differences between strips, tie points are determined by an interactive measurement. As laser footprints are discretely sampled, the selected tie points are almost not real laser footprint. We proposed a Virtual Tie Point Model to integrate the tie point and real laser footprints. Each VTPM contains a tie point and three real laser footprints, and two rules are defined to calculate tie point coordinate from real laser footprints. The flow of self-calibration based on VTPM is detailed described. The practical examples illustrate the feasibility and effectiveness of the proposed self-calibration method.