Abstract: Proper treatment measures for tunnel collapse can ensure the safety of tunnel construction and effective? ly avoid the secondary collapse. Based on the background of the collapse and cave-in event at the entrance of the tunnel of Shenzhen outer ring expressway, this paper analyzes the causes of the collapse, proposes the corresponding measures to deal with the collapse, and analyzes the treatment effect of the collapse by numerical simulation and monitoring measurement. The results show that the factors like upper-hard and lower-soft stratum, poor construction quality of pipe-roof and excessive blasting cycle are the main reasons to cause the collapse and cave-in of the tunnel; it can safely pass through the collapsed area with the combination of sandbag backfilling, radial grouting of small conduit, normal grouting at working face and concrete supporting at the arch bottom.