According to uniaxial loading-displacement curves of TC4 titanium alloy, The parameters of Gurson-Tvergaard-Needleman model (GTN model) were determined by an inverse approach. The influence of 6 different GTN model parameters on simulation results were studied by finite element method. It is found that only the parameters of f0 and fN need to be determined by the inverse approach, εn defined by tensile test, Sn determined by calculation, fc and fF could be given by simulation results directly. Voids damage evolution becomes faster with appearing of necking stages of TC4 titanium alloy, until failure fracture.