Blend materials were prepared successfully from twokinds of WPU with different NCO/OH molar ratiosand starch with different contents by solution casting.The certain extent of miscibility occurred betweenWPU and starch in the blend materials on the wholeratio of WPU to starch. With an increase of starchcontent, the WPU matrix with dispersed starch in theblends changed to dual-phase continuity, and finallyto starch matrix with dispersed WPU. Compared tothe blends containing WPU2 (1.75 of NCO/OH molarratio), the blends containing WPU1 (1.25 of NCO/OHmolar ratio) and 20 wt % starch exhibited significantlygood tensile strength, elongation at break, and tough-ness. Therefore, 20 wt % starch in WPU1 plays animportant role in improvement of various mechanicalproperties of the blend materials