About 175m of the shield tunnel on Guangzhou Metro Line 6 (Datansha Station-Ruyifang Station) crosses through Karst cave, and there during the construction, pre-treatment of surface grouting is made to the Karst cave and such measures as boring parameters optimization, residue volume and grouting volume controlling and residue soil improvement are adopted to make sure that the shield machine successfully crosses through the Karst cave. This thesis discusses about these construction technologies.