An adaptive control algorithm used in a practical adaptive optical (AO) system was analyzed. The adaptive control algorithm, differs like the traditional control algorithm, it considered the effect of atmospheric turbulence and the measurement noise together. The coefficients of the controller can change to adapt the working environment of an AO system to make the compensation optimizing. The experimental results on the 61-element AO system were analyzed, and the methods to solve some practical problems with the algorithm were discussed.