Abstract: This paper systematically summarizes the process of robot imitation learning and discusses related key problems in this field.Based on the biological mechanism of imitation,an engineering application framework on robot imitation learning is constructed in this paper.Guided by the framework,the research on imitation learning is reviewed,especially about the behavior representation and its research progress.Contrastive analysis between imitation learning and reinforcement learning is formulated in the process of learning motor skills.The future developments of imitation learning is prospected.Hence,the study of the robot imitation learning is a hot-spot of the research on biological bionic mechanism.