Load-displacement curves are obtained based on the monotonous conical indentation test under half cone angle of 70.3° and 60°. The relationship between the stress-strain curves and the load-displacement curves are found according to Kick’s law of load-displacement curves. After reasonable iteration, eventually uniaxial elastoplastic constitutive relationships of materials are obtained by FE calculation. Through the reverse application of two kinds of titanium alloy, the constitutive relationships obtained by iterative calculation are consistent with the classical uniaxial tensile test results.