Abstract: Block falls or slides are often encountered in various rock projects. To solve this problem, the stability analysis of the blocks should be done based on their geometrical conditions and relevant mechanical properties. Besides traditional projection on equatorial plane and numerical methods, a new method, coordinate projecting method, can be used in stability analyses of the blocks. After describing relevant principle, the authors provide an application of the new method in geometry analysis of the blocks and its computerization. In addition, a software CPH-1 based on the new method, has been developed by using Visual C++ language for convenience of geometry analyses. To demonstrate the effectiveness of the software, an example in underground engineering is also presented.