Abstract: The performance of porous shape memory polymer prepared by single relative molecular mass polyols cannot meet the requirements of well completion, so it is necessary to prepare a porous shape memory polymer with polyols in different relative molecular mass. In order to provide a basis for the preparation of porous shape memory polymers suitable for different downhole conditions, the different porous shape memory polymers are prepared by changing the relative molecular mass ratios of polyols. The influence of relative molecular mass ratios of polyols on their properties were analyzed by testing mechanical properties, glass transition temperature, and thermal sensitivity and by observing the pore structure. Larger relative mass ratio of low relative molecular mass polyols to high relative molecular mass polyols will bring higher hardness, compressive strength and bending strength of porous shape memory polymers; and it will cause lower temperature for glass transition, thermal deformation and the later recovery, and smaller opening rate; moreover, it will lead to larger foaming pore size, pore coefficients and pore wall thicknesses, and stronger structural anisotropy. The research demonstrated that a porous shape memory polymer for well completion can be obtained by adjusting the relative molecular mass ratios of polyols, this kind of polymer for completion has certain mechanical strength, it can meet the requirement for shape recovery under different downhole temperature conditions, possessing the filtering function for formation sands with different radius sizes.