Abstract: Table look-up method used in the Heterodyne Receiver to detecting the received signal strength is unable to establish proper function table of multidimensional data,and the test results are instable,the detect errors are large at nonlinear part of the system.To solve these problems,this paper proposes a new method to establish the training network based on BP algorithm by acquiring the value of local oscillation Automatic Gain Control(AGC),intermediate frequency AGC and the average voltage of the detector output,which can then be used to establish the corresponding relationship with known signal strenth of the input,and these data are used as training data and testing data in the network for training and testing.Simulation and experiment results prove that the proposed method is efficient and can reduce the detection error.