Abstract: Taking into account the multipath signals, the multi-channels disturbances with non-stationary characteristic and stationary noises, the methods of time delay estimation without regard to multipath signals can’t attain accurate time delay; even the behaviors of estimation are deteriorated. Therefore, the constrained adaptive multipath time delay estimation based on cyclostationarity is proposed in this paper, and the convergence behaviors of multipath time delay estimation of this method are derived. This approach which can refrain the affection of disturbances and noises effectively can attain time delay and multipath time delays which are not an integer multiple of sampling interval accurately and directly at a low signal-to-noise ratio environment, and it is also useful for the case when the noises are spatially correlated, while the traditional method can’t attain both time delay and multipath time delays which are not an integer multiple of sampling interval directly. The simulation examples are presented to demonstrate the effectiveness of this new method.