Abstract: The results from the consolidated drained triaxial compression tests on the municipal solid waste (MSW) with four kinds of compositions,have shown the relation curves of pore water pressures and times and axial strains. The pore water pressures that exist in MSW and soil are different. The distributing of pore water pressure of MSW is very complex. The pore water pressure exist in pore,on impervious materials and in organic matter. It is nonlinear distributing and discontinuous along the depth. So,the application of principle of effective stress of soil mechanic is unsuitable here. It is suggested that the consolidation of MSW should not be considered and the settlement of MSW should be divided into compression and biological decomposition.