In this paper, the ligand field method is applied to derive an analytic expression relating the charge transfer between M and Mo6S8 cluster and the splitting of the 4d orbitals of Mo atom for Chevrel phase MzMo6S8 compounds. From the reflection spectrum of PbMo6S8 the charge transfer from Mo6S8 cluster to Pb atom is calculated to be 1.18 instead of 2 electrons being transferred from Pb atom to Mo6S8 cluster as generally recognized in previous literatures. The number of 4d electrons on Mo6 is therefore 18.8.