To achieve small residual wavefront gradient tilt corrected by the adaptive optics system and good robust stability of the system, a mixed H2/H∞ control method for the adaptive optics system was proposed. In order to verify the control performance, the atmospheric turbulence wavefront gradient tilt was simulated, and the residual wavefront gradient tilt corrected by the adaptive optics wavefront gradient tilt correction test platform with the mixed H2/H∞ controller and by the one with the classic integral controller was compared. The robust stability of the two systems was compared as well. The result demonstrated that the test platform with the mixed H2/H∞ controller achieved not only smaller residual wavefront gradient tilt but also better robust stability compared to the one with the classic integral controller, and proved the efficiency of the mixed H2/H∞ control method for the adaptive optics system.