A section of Yesanguan tunnel on Shanghai～Chengdu highway passes through a superhuge karst collapse accumulation body. The construction technologies for the mentioned section of Yesanguan tunnel, including advance reinforcement, tunnel excavation and floor consolidation, are presented in the paper. Such countermeasures as long forepoling reinforcement assisted with pregrouting, top heading/bench excavation method, Ishaped steel ribs and floor grouting consolidation are taken during tunnel construction and good results have been achieved.