This work aims at investigating the mechanical properties and behaviors of orthorhombic Cu3Sn crystals at room temperature through molecular dynamics (MD) simulation. The focuses are placed on the tensile stress-strain behaviors and properties of the Cu3Sn single crystal and also their dependence on applied strain and strain rate. An attempt to characterize the deformation evolution of the Cu3Sn nanostructure during the stress-strain test is also made. In addition, the elastic properties of bulk polycrystalline Cu3Sn are estimated, as a function of strain rate and applied strain, by using the monocrystal results. The effectiveness of the MD model is demonstrated through comparison with the nanoindentation results and also published theoretical and experimental data. The calculated orthotropic elastic and shear moduli and Poisson's ratio of Cu3Sn single crystal reveal not only high anisotropy, but also the great effects of applied strain and strain rate only as the strain rate exceeds a threshold value of about 0.072% ps(-1). Specifically, raising the strain rate increases the orthotropic elastic properties and also the ultimate tensile and shear strengths of the nanocrystal, whereas increasing the applied strain reduces them.