Collective cell motion is crucial for various physiological and pathological processes, and it highly relies on physical factors in cell microenvironment. However, a quantitative understanding of the effect of the physical factors remains lacking. Here, we studied the collective motion of cells on patterned matrixes with experimental study and numerical simulation by quantitatively analyzing the features of cell collective motion. We found that the collectivity of cell motion is size-dependent. The cells have high collectivity on a small pattern, while they lose the collectivity on the large one. The geometry of the pattern also influences the collective motion by regulating the velocity distribution in the cell layer. Interestingly, the cell density can significantly influence the collective motion by changing the active stress of the cells. For a quantitative understanding of the mechanisms of the effect of these physical factors, we adopted a coarse-grained cell model that considers the active contraction of cells by introducing cell active stress in the model based on the traction-distance law. Our numerical simulation predicted not only the cell velocity, cell collectivity, and cell polarization, but also the stress distribution in the cell layer. The consistency between the numerical predictions and experimental results reveals the relationship between the pattern of collective cell motion and the stress distribution in the cell layer, which sheds light on the studies of tissue engineering for biomedical applications.