In order to improve the accuracy, a high precision alignment of laser inertial navigation system was proposed based on the attitude tracking approach for a rocking base. The low frequency changes of the attitude angle could be considered as a useful signal that reflects the true motion of the base, which should not be removed, but should be tracked. The coarse alignment was carried out in the inertial coordinate system, which was sensitive to attitude change and could track the attitude swaying. The alignment errors were ensured to be a small value after the coarse alignment. The standard Kalman filter was employed in fine alignment to avoid to use the complex nonlinear algorithm. Two horizontal accelerations were added into the measurement vector besides of two level velocities, which can improve the tracking capability of Kalman filter. The alignment accuracy was checked by the repetitiveness of the final alignment results with the alignment from different starting time to the same end time. A high precision laser strapdown inertial navigtion system was used to verify the algorithm. It is shown that the alignment precision is about 0.04° by the alignment experiment on rocking vehicle, and the alignment time needs 180 s, the level position error is 770 m/h, and the proposed algorithm can satisfy with need of the high precision laser inertial navigation alignment.