Abstract: 3D laser scanning technology has been more and more widely used in detection of cavity，but point cloud obtained through it often need to be processed and analyzed by several software.Hence，a large amount of time was wasted and the complex operations of the software also limited the utilization of later data.To solve these problems，and based on VS2010 platform，a cavity point cloud processing system was developed independently by using PCL and HOOPS.This system consists of point cloud management module，3D display module，point cloud filtering module，cutting and 3D modeling module and application module.And its function was easy to be extended by using the modular design ideas.According to the demand for accuracy of cavity measurement，point cloud could be filtered and simplified.So the following 3D modeling and display was accelerated；The system integrated with common functions of 3D modeling，cutting and analysis，and volume calculation of cavities，and it was easy to use and provided conveniences for on-site technical personnel to make decisions.This system could provide scientific basis and technical support for cavity government and parameter optimization and also have the positive significance in promoting scientific and visualization of cavity government.

Key words: Cavity scanning, PCL, Point cloud processing, 3D laser scanning