In the application of pulse-coupled neural network(PCNN),it is difficult to set the parameter of pulse-coupled neural network. In the pulse-coupled neural network model, the linking coefficient β plays an important role. According to the relative entropy D(P, Q: t) and standard deviation, educe an estimate formula that to set the linking coefficient β automatically in the simplified pulse-coupled neural network model. Experimental results show that the algorithm gets a better visual effect when dealing liver hydatid disease image,showing great adaptability.