Abstract: In order to overcome the irrationality of personal decision about supporting and realizes expert's group decision making,the intelligent expert system for the supporting design of tunnel was developed with object-oriented technology and visual design method,which includes the total planning thought,repository establishment,reasoning mechanism debugging and so on,and neural network technology was used in this system.The system is used for the decision-making on a certain supporting design scheme,its running result is very close to the expert's recommended precept.