The utility model provides an assist device for the cervical cerclage. The assist device is characterized by comprising a cavity, a hollow push rod, a Y-shaped pipe and a water sac cavity. One pipe part of the Y-shaped pipe is a drainage pipe connected with the water sac cavity, another pipe part of the Y-shaped pipe is a water injection pipe, and the last pipe part of the Y-shaped pipe is a water outlet pipe. The water outlet pipe is a sealed pipe. A water sac support is arranged at the front end of the hollow push rod, the drainage pipe penetrates through the hollow push rod, the water sac cavity is located in the water sac support, and the hollow push rod penetrates through the cavity. The water sac support is composed of two or more wings capable of being closed. Before the cervical cerclage, the amniotic sac is lightly pushed upwards to provide enough space for suture by operators and is protected well.