Abstract: CIPW is one of the most extensively used petrochemistry calculating methods. Its purpose is to provide a basis for rock naming by simulating mineral components and relative amounts. The author found that the calculating principles and methods in different textbooks are various, that is unconvenient in practical application. After discussing the calculating method of plagioclase serial number, CIPW calculating principle and albite distributing way, the author concluds that:1) as calculating the plagioclase serial number,the amount of albite should adopt two times of albite molecular number; 2)when MgO'+FeO″>SiO₂'>0.5(MgO'+FeO″),we should use the following hypotheses:Hy+Ol=SiO₂',and Hy+2Ol=MgO'+FeO″;and 3)Rittmann method is suggested to name rocks, as it is more reasonable and accurate.