Structural properties and interlayer interaction in mutually incommensurate (MX)(2)TX2-type ternary chalcogenides with layered composite crystal structure have been investigated on the basis of structure analysis including superspace group symmetry. It has been confirmed that charge transfer between substructures occur in (LaS)(x)TiS2 from the results of Ti K XANES spectra. The lattice stability and interlayer interaction in the (MX)(x)TX2 have been discussed with the use of bond-valence sum (BVS) method by considering modulated structure analysis.