In order to understand the mechanisms of micro-slip initiation and propagation at the contact interface, a visualization method of partial micro-slip at the contact interface was developed. The process of micro-slip initiation and propagation at the contact interface was successfully observed, and the relationship between tangential coefficient and partial slip distribution at the contact interface was analyzed by using the newly developed method. It was clarified that the partial slip distribution was affected by contact morphologies such as spherical ball, triangular stamp, rectangular stamp and concave stamp contact. The effect of uneven area of the contact surface on the micro-slip initiation and propagation was also clarified. It is confirmed from observed results that the visualization of the partial slip at the contact interface is useful for understanding the mechanism of the micro-slip initiation and the propagation at the contact interface.