Abstract: Guidance of submarine- launched anti-ship torpedo is influenced by sea environment, which restricts the submarine attacking distance and the torpedo homing distance. As a result, the author makes use of the design con- cep-tion of anti-radiation missile to present a new combined guidance based on target detection and other guidance ways. The anti-active sonar torpedo adopting the proposed combined guidance takes active sonar pulse signals from anti-submarine ship and torpedo as its guiding source in attacking target. In addition, the design principle and charac- teristics of the anti-active sonar torpedo with the combined guidance are addressed, and its operation process is supposed. The analysis shows that the anti-active sonar torpedo with the proposed combined guidance meets the requirements for actual attack.