The design approach of H∞ autopilot for autonomous underwater vehicles (AUVs) is proposed. Comprised by the three sub-controllers,i.e. speed,heading and depth controllers,the designed autopilot has advantage over existing H∞ control of AUVs. The overshoot in speed,heading and depth control systems under step commands is restricted by refining the weighting function for robust stability. The dynamic performance of heading and depth control systems is improved by feeding back yaw rate and pitch angle,respectively. To evaluate the design approach,it is then utilized to synthesize the autopilot for flight control of Subzero Ⅲ,a low cost test-bed for AUV control techniques. Both simulations and water trails verify the effectiveness of the design approach. The design approach of H∞ autopilot for autonomous underwater vehicles (AUVs) is proposed. Comprised by the three sub-controllers, ie speed, heading and depth controllers, the designed autopilot has advantage over existing H∞ control of AUVs. The overshoot in speed , heading and depth control systems under step commands is restricted by refining the weighting function for robust stability. The dynamic performance of heading and depth control systems is improved by feeding back yaw rate and pitch angle, respectively. To evaluate the design approach, it is then utilized to synthesize the autopilot for flight control of Subzero III, a low cost test-bed for AUV control techniques. Both simulations and water trails verify the effectiveness of the design approach.