In this paper, a systematic investigation on the quasi-static and dynamic deformation behavior of two tantalum-tungsten (Ta-W) alloys, namely Ta-2.5 weight percentage W (Ta-2.5W) and Ta-10 weight percentage W (Ta-10W), is presented. It is shown based on the performed SHPB and Taylor impact tests that the yield stresses of tantalum-tungsten alloys exhibit sensitivity to strain rate and W content. Based on the quasi-static and high strain-rate experimental data, the material constants in Johnson-Cook (JC) model were obtained for the two Ta-W alloys. In addition, validation of the derived constitutive model is carried out through comparison of Taylor impact inhomogeneous deformations under high strain rate (103~104 s-1), obtained from simulations, with their experimental counterparts. It is shown that the simulation results agree well with post-test geometries in terms of side profiles and impact-interface footprints for Taylor impact tests. To bridge the different spatial scale involved in the process of tantalum-tungsten alloy deformation, a meso-scale research is proposed via a optical microscope (OM) image analysis. The results presented in this paper, provide new insights into the mechanisms suitable for the constitutive relations determination process.