Taiwan is a mountainous island and meanwhile located along the tectonic boundary of the Eurasian continental plate and the Philippine sea plate. Therefore, it has a very complicated geological structures and is a severe challenge to tunnelling works. Many national development projects such as water transmission lines, railway and highway projects, and hydropower development projects, involve lots of tunnelling works. Those tunnelling works both size and scale have been increased significantly from time to time. And the construction techniques have also been improved substantially from project to project. For instance, in the early stage, tunnel excavation was carried out by hand while nowadays is carried out by tunnel excavation machines. In this paper, the geological features, which are closely related to tunnelling works are outlined. Then, some technical developments such as support systems etc. are presented. Finally, handling of difficult ground is illustrated. It is hoped that the experience learned in the past can be utilized in the similar projects in the future.