Plasticity in body-centered cubic (BCC) metals is known to have a strong temperature dependence and strain-rate dependence, which stems from the thermally activated motion of screw dislocations. The Taylor impact test can subject a sample to high strain-rates and temperatures, creating a gradient of stresses and strains. Recent experimental findings have shown that tantalum single crystals display strong anisotropy during Taylor impact testing in stark contrast to their polycrystalline counterparts. To investigate the mechanical response during extreme condition with high-strain rate requires an integrated computational model which can capture both defect microstructure characteristics and the macroscopic constitutive behaviors of the materials. In this regard, dislocation dynamics (DD) simulations can be a useful tool in studying dislocation-mediated plasticity, which is widely believed to contribute to deformation behaviors at high strain-rates. Recently, we develop a multi-scale plasticity model which could capture detailed dislocation motions and corresponding macroscopic response by coupling DD with a finite element model. In this talk, we present simulation results of the dynamic loading during a Taylor impact test and track the intricate detail of the dislocation microstructure. Our model is capable of predicting similar anisotropic response observed in the experiment.