Abstract: In order to develop an autonomous geometric preprocessing module and, moreover, adapt to the future large-scale parallel computing, the content of ray tracing efficiency is studied. Based on the constructive solid geometry, CSG, and the point-line geometry, which are implemented respectively in OpenMOC and KYLIN-2, the serial tracing efficiencies under these two geometric descriptions are compared. The ray tracing procedure of KYLIN-2 is parallelized in space considering the physical meaning. The results show that with the help of Computer Aided Design, CAD, modeling tool and parallel ray tracing in space, the efficiency of ray tracing has been obviously improved under the point-line geometry. Parallel ray tracing in space is feasible and achieves parallel scalability with high speedup ratio.