In signal detection of the complex environment, the clutter environment where a target is located can not be pre-determined, at this time the use of targeted single CFAR detection strategy tend to have varying degrees of loss, and flexibility is poor. Therefore, a multi-strategy CFAR detection algorithm based on adaptive threshold selection is used, combining the advantages of CA, GO and ACCA detection algorithms, and the corresponding strategies are selected reasonably by judging the current clutter background. In addition, the distributed CFAR system using the composite algorithm as a local detector is studied and the fusion criterion adopts “and” and “or” rules. Finally, the performance of the algorithm is verified by simulation.