In order to detect weak signal in complex background, the paper studies and realizes six-channel digital receiver. Receiver is designed as much digital structure as possible, the basic hardware parameters of receiver can be adjust to meet different needs of specific applications by calling the corresponding software packages. Compared with the conventional receivers, the receiver has virtues of high sensitivity, low power consumption, standardization and software-based. The receiver has been applied in a target detection system, the experiment results show that the method is very promising.