| A lane-based optimization model for lane function and signal phase at intersection was established, considering the interaction of complex factors such as different approaches, different flow directions, different lane functions and different phase schemes. The objective function of the model was to minimize the critical flow ratio of the intersection, to consider the constraints such as lane balance, flow matching, lane function conflict, shared lane saturation, and to optimize the entrance and exit lanes at the same time. The solving algorithm for the proposed model was given. The proposed model has fewer variables, better connection with the current traffic design methods, and can get the global optimal solution. Moreover, the solution method is relatively simple. The case study shows that the proposed model can effectively reduce the critical flow ratio, cycle and vehicle average delay at intersections.