In the basis of gathering the construction knowledge in the past，the computer OOP programming technology is adopted，and the intelligent decision-making aided system is developed for road tunnel excavation process. All the function modules in the system are achieved through the computer，which include the total planning thought，establishment of knowledge repository，reasoning mechanism debugging and so on. The system is used for the decision-making for a given supporting design scheme in Inner-Mongolia autonomous region，and its running result is very close to the expert¢s recommended precept.