This paper investigates the main mechanical properties of TC1 titanium alloy sheets with different thicknesses, and a useful function that can describe the mechanical properties reasonably through extensive practical application will be used. Meanwhile, planar anisotropies of above TC1 titanium alloy sheets were fully studied by Barlat''89 and Yld2000-2d yield functions with an aim of the influence M value on describing ability for distribution characteristics of material yield stress and anisotropy parameter and comparison of their performances on above titanium alloy sheets.