Reflected waves in water tank are the key interference on model test results. Active absorbing wave making system eliminates interference waves in tank, and provides a long time good test environment for related hydrodynamic test. Basing on Airy wave theory, active absorbing wave-making method is put forward, and control equation of rocking-plate wave maker is derived. Using AC servo-control technology, active absorbing wave making control system is designed based on the method mentioned above, and active wave making control software is compiled. Through three feedback routes, it realizes that the precise control of a wave maker, the interference waves absorption, the output of a target wave. When the output wave elements are same, the experiments adopt absorbing and non-absorbing wave making method. Comparison test results show that the feasibility and effectiveness of active absorbing wave method. Finally, the active absorbing wave making method improves the quality of waves, reducing interference of reflected waves.