Abstract: For global optimal path planning of mobile robot,a linear operation based traversal algorithm is proposed firstly.This algorithm computes the step transform matrix(STM) by field scan at first,and then searches the shortest path in the STM with consideration of search direction coherence.Thus a global shortest path which avoids unnecessary turn is planned.Secondly,a new evaluation criterion is proposed to distinguish whether paths are excellent or not.Finally,path planning comparison experiments are conducted with round wave propagation algorithm by simulation.The results show that the algorithm can find better path than wave propagation algorithm under the proposed criterion.