Abstract: Some of the women who will experience surgical abortion were found the poor flexibility of cervices， so adequate cervical preparation before surgical abortion is necessary. Adequate cervical preparation can reduce the difficulty of surgical operations and reduce the incidence of cervical injuries markedly. There are many cervical dilation methods. One of the methods is osmotic dilators such as laminaria， made of natural seaweed. When the laminaria is placed into the cervical canal， it will absorb water of the cervical secretions and expand gradually. At the same time， cervical canal will be expanded and ripened softly. Many studies have shown that laminaria can achieve a good role to expand cervical canal abortion before surgical abortion and its effectiveness maybe superior to drugs such as mifepristone， the metal dilators and synthetic osmotic dilators. The evidences have also shown that the laminaria does not increase uterine perforation， infection，anaphylaxis and other adverse reactions. Cervical dilatation method，including laminaria，must be used for those women who really need and also must be informed- choice by the women themselves to avoid unnecessary waiting time and additional medical burden.

Key words: Surgical abortion, Laminaria, Dilatation of cervical canal