Abstract: The middle line of South-North water transfer project is a key construction to make water using in safety in the north area of China, especially in Beijing and Tianjin areas, where the tunnels for water transfer on Beijing section is a crucial part of the whole project. Based on a geat deal of field investigation, and the relative data analysis on the tunnels for water transfer on Beijing section, engineering geological conditions of the tunnels are introduced in detail, including Xiganchi Tunnel, Chongqing Tunnel and Xisihuan Tunnel. It is shown that the tunnels are different in terrain, stratum, geological structure and hrdraulic condtions although the three tunnels are in the same area. Also, the major engineering geological problems are discussed and analyzed, and some suggestions and effective measures are proposed.