Abstract: Artificial leg (prosthesis) has been a leading-edge research object in the fields of robotics and biomedical engineering. In this research, the intelligent artificial legs developed by the United Kingdom and Japan in the middle of the 1990s reflect its newest progress. This paper includes five sections. The first section is an introduction. In section 2, we mainly introduce the study of artificial legs in foreign countries before the early of the 1990s. Section 3 deals with the foreign researches on artificial legs from the early of the 1990s to the present, and its emphasis is focused on the intelligent artificial legs. In section 4, we briefly introduce the domestic research work in this field. In the final section, the development trend towards study of artificial legs is proposed.