In this paper, 3 key construction technologies, including safe overburden thickness, influence on dike, and tunnel segment structure and connection waterproofing of large diameter tunnel crossing underneath Yellow river, are studied. Conclusions drawn are as follows: 1) Minimum buried depth of tunnel and the longitudinal alignment of the tunnel are obtained; 2) Influence on dike is checked; 3) Tunnel segments, segment joints and elastic gasket used for waterproofing of tunnel segments are designed, and the waterproof reliability of segment joints is checked.