The in-cylinder three-dimensional unsteady analysis on the fluid patterns were scrutinized using computational fluid dynamics code. The 3D CAD data were created using the 3D CAD modeling software and the computational meshes were generated considering the movements of intake valves and piston. The calculated results of in-cylinder flow patterns for the pent-roof type combustion chamber were in good agreements with the unsteady water rig experimental results. To investigate the influences of the intake port inclined angle variations on the in-cylinder flow patterns and the resulting in-cylinder tumble ratio, each type of intake port were simulated with the intake port inclined angle variations. The results show that as the intake port inclined angles become smaller, the in-cylinder tumble ratio were strengthened. If the intake port inclined angle was larger than 30 degree, the in-cylinder tumble ratio was saturated. For the global in-cylinder turbulent kinetic energy level, the values were decreased as the intake port inclined angles were increased.