Abstract: An autonomous gait selection algorithm based on C4.5 decision tree for quadruped robot is proposed to solve the autonomous gait selection problem of quadruped robot between static and dynamic gait. First of all, four main factors that affect the static and dynamic walking of quadruped robot are studied: terrain complexity, speed, cost of transport and stability. Then, taking the above four factors as the basis of static and dynamic gait selection, an autonomous gait selection algorithm based on C4.5 decision tree is investigated. And the autonomous decision rules of static and dynamic gait are obtained through training. Finally, combining the improved A* path planning algorithm synthesizing six objective factors weighting, the effectiveness and feasibility of the proposed algorithm are validated by simulations.