Two rehabilitation options for Haizhongzhou tunnel are described and proper option is selected. Countermeasures are taken in tunnel collapse treatment, excavation and monitoring. Conclusions drawn are as follows: 1) Crosssection enlarging option is the proper option for the rehabilitation of Haizhongzhou tunnel. 2) Strengthened support parameters, ground reinforcement by grouted rock bolts installed from the ground surface, collapse treatment and backfilling are suitable for the rehabilitation of the tunnel. 3) The enlarging excavation should be executed under the protection of the existing lining, and the temporary support should follow the excavation immediately and should be closed to form a ring as soon as possible. Monitoring should be strengthened during the rehabilitation so as to guarantee the safety.