It is conceptually proposed that the total entropy of polymer solution is contributed from two distinct parts: the positional and the oomformational. The former can be represented analytically, while the latter can be simulated with the random self-avoiding walk model on the simple cubic lattice for multichain systems. The obtained results indicated that both the conformational entropy and the mixing heat are consistent with the scaling laws wry well. It is conceptually proposed that the total entropy of polymer solution is contributed from two distinct parts: the positional and the oomformational. The former can be emulatedaly, while the latter can be simulated with the random self-avoiding walk model on the simple cubic lattice for multichain systems. The resulting results indicated that both both conformational entropy and the mixing heat are consistent with the scaling laws wry well.