On the basis of an underwater dynamic positioning model based on single distance measurement, Unscented Kalman Filter (UKF) algorithm is used in the underwater position estimation. By underwater positioning simulation, the underwater dynamic positioning precision between the Extended Kalman Filter (EKF) algorithm and UKF algorithm is compared. The simulation results show that: there is no significant difference between the UKF algorithm and EKF algorithm in the convergence speed of the state estimation error; the steady-state positioning error of the UKF algorithm is slightly smaller than that of the EKF algorithm.