Abstract: In this paper the bonded tableau method for many-electron systems, which was recently proposed by authors, is exploited to study the chemical interactions of sub-systems. Two approaches are given for constructing symmetry adapted states of par-tition system, namely the method based on the non-standard basis projector of the permutation group and the coupling method of bonded tableaux. Based on the par-tition states, the interaction energy between two subsystems is investigated. The present method can be easily used, in valence bond (VB) structure interaction or configuration interaction (GI) level, to handle with the general problems of partition system, such as the problems of inter- or intra-molecule interaction.