Concerning the defect that Volterra structure equalizer has large amount of computation, an improved adaptive equalizer of nonlinear satellite channel was proposed, and a new cascade structure of a linear equalizer and a nonlinear equalizer were obtained by analyzing the truncated Volterra series. The third-order nonlinear memory term multiplying in the Volterra equalizer expression was converted to second-order nonlinear memory term multiplying in the new structure equalizer. When signals passed through the equalizer, the number of complex multiplications was reduced. The simulation results show that the number of complex multiplications of improved nonlinear satellite channel adaptive equalizer is 1/9 times as that of Volterra equalizer when channel has strong memory depth. Meanwhile, 16 Amplitude Phase Shift Keying (16APSK) signal equalized by the improved adaptive equalizer has more compact constellation points.