Abstract: A tracking filter algorithm based on the maneuvering detection delay is presented in order to solve the fuzzy problem of target maneuver decision introduced by measurement error of active sonar. When the maneuvering detection is unclear, two target moving hypothesis of uniform and maneuver form the method of multiple hypothesis tracking is generated to delay the final decision time. Then construct hypothesis test statistics based on residual sequence. With the sequential probability ratio test, the algorithm improved the active sonar's tracking ability of unknown prior information target and integrated the advantages of strong tracking filter and Kalman filter. Simulations show that the algorithm can not only track the uniform targets accurately, but also track the maneuvering target steadily. Sea trial data processing result further verifies the effectiveness of the algorithm for real underwater acoustic target.