Cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) is among the most common stationary phases used in chiral separation column. Nevertheless, there is no crystal structure of CDMPC reported yet for reference. Modelling studies of CDMPC so far have been based on the basis of the parameterized structure of the dry crystalline structure of cellulose tris(phenylcarbamate) (CTPC) predicted in late 80s. Solvent effect was not considered explicitly in those studies. In 2016, Okada et al. reported that the number of monomeric units of CDMPC would influence the structure of the chiral stationary phase (CSP), and hence the chiral recognition ability. However, most of the previous modelling studies ignored the chain-length effect and considered CDMPC with at most twelve residues. In this study, the effects of explicit solvent and number of residues on CDMPC are investigated specifically. Modelling of two chain lengths (9-mer and 18-mer) of CDMPC using molecular simulation in both implicit and explicit solvent environments were performed. Predicted elution order of selected enantiomers on 18-mer CDMPC agrees better with experiments. Design principles of polysaccharides-CSPs were discussed based on this study.