The rip current is a strong current, perpendicular to the coastline and towards the open seas. It is very dangerous for people at the beach, and once carried away from the shoal by the rip current, inexperienced swimmers will find it difficult to swim back to the shore and will eventually be drowned due to the exhaustion. Most drowning accidents in the coastal area are associated with the rip current. The lack of public awareness about the rip current is one important cause. This paper reviews the damage, the development, the characteristics and the classification of the rip current from the perspective of hydrodynamics, and some suggestions are made of how to prevent the rip current and ensure the safety.