Fabrication of Ag or Au nanocolumns by oblique angle deposition (OAD) is now prevalent for their surface enhanced Raman scattering (SERS) property and their biosensor application. However, the size, shape, and the density of nanocolumns are not directed in a desired way. To sufficiently realize the growth process controlled by multiple physical factors like deposition angle (\alpha), substrate temperature (T), and deposition rate (F), we develop a three-dimensional (3D) kinetic Monte Carlo (KMC) model for simulating processes of Ag nanocolumnar growth by oblique angle deposition. The dependences of nanocolumnar morphologies on these factors are analyzed. The mimical results reach a reasonable agreement with the experimental morphologies generated by OAD.