As the precision of roll angle of a star sensor is much lower than that of pitch/yaw angles, it has great impact on the course precision of a space tracking ship. By considering the actual working environment of the space tracking ship, an efficient ship attitude determination method based on optical axis pointing of a dual star sensor was proposed. Firstly, the principle and the shortages of ship attitude determination method based on the single star sensor were presented, and the impact of roll angle of star sensor on ship attitude measurement precision was analyzed. Then, a new attitude measurement system based on dual star sensors was constructed, and its calculation model based on optical axis pointing was built. Finally, the outdoor experiments were carried out to verify the precision of the algorithm model. Experimental results indicate that the accuracy of ship attitude based on dual star sensors can reach to 6.9″, 5.7″and 4.5″ for the course , pitch angle and the roll angle, respectively. Comparing to the single star sensor, the precision of ship attitude determination is improved greatly, and the impact of roll of star sensor on course of the ship is avoided, which offers useful references for engineering application of star sensors used on space Tracking Telescommanding and Control (TT&C) ships.