Walking training is one of the most important rehabilitation processes with paralysis patient. Walking training by using an orthosis can help advancing a patient's independent level. The 1-DOF walking orthosis which compensates the demerit of the existing orthosis and securespatient's mobility has been proposed. New orthosis has been designed under the following two premises. First, the knee joint of the orthosis was designed fold in order for the orthosis to move in a walking pattern similar to that of a normal person. Second, the knee joint was designed to extend during the swing phase and lock safety during the stance phase.