According to free configuration space, the skeleton graph of working environment of mobile robots was constructed. The length of link of skeleton graph was quantified according the actual length of pathway and presented with quantitative length matrix. The width of link of skeleton graph was quantified by the width rate of pathway and robot body, and presented with quantitative width matrix. For a pathway with width changing, the width was quantified according to the minimum width of the pathway. For multiply pathways between two vertexes, the pathways were merged into one pathway. In dynamic environment, the matrix value of link was set to -1 for a pathway with obstacles. In Dijkstra algorithm, the coordination path planning of multiply robots was implemented by comparing the remaining capacity of pathway width and the robot body.