The principle of rock cutting by means of water jet is presented, key parameters and methods for tunnel excavation by means of water jet are investigated, comparison and contrast is made among 3 waterjetbased tunnel excavation schemes, i.e., tunnel excavation by means of only water jet, tunnel excavation by mechanical method cooperated by water jet and tunnel excavation by mechanical method assisted by water jet, in terms of technology and economic efficiency. The calculation made verifies the feasibility of tunnel excavation by mechanical method cooperated by water jet. Conclusion is drawn that excavation by mechanical method cooperated by water jet can meet the requirements of the economic efficiency, advance rate, operation environment and risks of tunneling.