Many kinds of isolation systems trend to become larger and more complicated. But the multiple error LMS algorithm used in such systems will increase the computational complexity and be difficult to be implemented. So the decoupled multichannel active control algorithm based on FXLMS algorithm is studied and the simple adaptive controllers which can drive the actuators of each subsystem independently are designed. The outputs of error sensors of relevant subsystems are only applied to adjust the control force of the corresponding actuators. When the sum of squared outputs of the error sensors is minimized, the active control for the vibration with multi-degree of freedom will be realized. The simulation and test results show that the decoupled algorithm applied in the active vibration isolation system is simple and effective by adjusting the convergence coefficients and effort weighting factors.