An MDI system non-temperature sensitive memory sponge suitable for a flat foam foaming process is made by using a polyol mixture, which includes a polyether polyol and a polymer polyol, to react with an isocyanate and an auxiliary agent mixture that includes: a chain extender, a foaming agent, a pore adjusting agent, and a catalyst. The polyether polyol includes a polyoxypropylene glycerol with a molecular weight of 700 and a polyoxypropylene trihydroxy ether with a molecular weight of 4800, the polymer polyol includes a graft polyether, and the isocyanate is methylene diphenyl diisocyanate.