The calculation accuracy and time of the advance pointing angle are extremely important, which directly affect the tracking accuracy and debris ranging distance of a laser ranging system. When the optical angle measurement data of extremely short arcs is used for orbit determination, the sparse observation data often lead to non-convergence of orbit determination results, and thus it is impossible to calculate the accurate advance pointing angle using a traditional method. A new calculation method for advance pointing angles is proposed. Specifically, the data of the inertial sensor and optical detector carried on the satellite platform is used, and the angular velocity of relative motion is calculated by the data fusion algorithm based on the Levenberg-Marquardt algorithm. Then, the advance pointing angle is obtained by combining the relatively accurate distance information in orbit prediction. Under the working conditions of orbit determination using optical angle measurement data of extremely short arcs, the error of the proposed method is less than 0.1 μrad, and the minimum convergence time is 10 s, both of which are superior to those of the traditional calculation method and can meet the pointing accuracy requirements of the laser ranging system.