The direction of arrival (DOA) of multiple targets was acquired by solving non-liner correlation equations involving acoustic pressure and particle velocity with quantum particle swarm algorithm. In order to improve the precision, the DOA tracks of multiple targets were fitted with the method of least squares, the prediction model was found and then the DOA tracks were optimized by Kalman filter. The results indicate that the DOA of multiple targets can be resolved with the single vector hydrophone and the results should be expressed by statistic characteristics. The maximum number of unknown sources is 7. As the number increases, the DOA error is more serious. When the signal to noise ratio is higher, the resolution ratio and precision are also higher and the deviation is smaller. More importantly, the precision of DOA can be improved effectively by the method of data fitting and the Kalman filter. 