Abstract: Constants C 1-C 14 in 14 equations of the relationships between the K¨ubler，Weaver and Weber indices were deduced and calculated. Four formulae of the relationships between exponent u of the Pearson VII function and C 5, C 6, C 11, C 12 were deduced also. Therefore, those 14 equations can be directly used for actual converting analysis. According to the shape parameter Sc＝0.731 for the XRD peak of illite from Alpine flysch and using these equations the boundaries of anchizone of Weaver and Weber indices were calculated as 5.8-17.6 and 300-179, respectively.Application in distinguishing illite/smectite mixed-layer phase in air-dried condition was discussed on the basis of the added principle of XRD peaks.