Due to the complexity and uncertainty of factors affecting the underground construction, utilization of previous experiences as guidance in solving new problem is the major trend of engineering design for such projects. The rapidly developing artificial intelligence technologies, including expert system, case-based reasoning and artificial neural network, can provide an effective way of solving new problem by using experts' experiences or engineering case histories. Based on the preliminary results of applying the artificial neural network to rock tunnel support design and prediction of diaphragm wall deflection in braced excavation, it appears that the artificial neural network can be a viable method in providing design recommendation or predicting engineering performance by using the previous case histories or monitoring data.