The function and development of geological prediction are summarized. The misunderstanding of geological prediction and problems of various instruments are analyzed. The concept of geological prediction system is proposed. The contents of geological analysis technology of the tunnel area，prediction technology of bad geological bodies

and warning technology for close major geological disasters are illuminated. The steps of geological prediction system are as follows: the geological factors are classified by intricacy according to the conclusions of geological analysis technology and standards for intricacy classification of geological factors; different programs of geological prediction system are formulated for different geological intricacy degrees; and dynamic control on the site is considered. The geological prediction system is applied to an example of F3 weathered slots of Xiamen subsea tunnel. Finally

the development trend of geological prediction system is put forward. The purpose of this research is to improve the geological prediction work，make the geological prediction results really play a guiding role in the construction process on the site

so as to decrease the investment and casualties of the project to the best extent.