Abstract: This paper deals with coordination and obstacle (or collision) avoidance between mobile robots in conflict areas, that is, intersections. The planning approach both concentrated and distributed is adopted. Each mobile robot's path is planned according to the topological structure of the system; the distributed planning for motion characteristics of each robot is given using priority strategy in intersections. The intelligence of the whole system is improved by blending intelligence of the high and low levels. At the same time, a set of traffic rules is set up to make planning for the system easier and each robot in the system reachs the goal position of itself with safety as quickly as it can. In order to deal with the uncertainty introduced by the dynamic world, the planner operates periodically. At last, an emulation result is given.