According to a large number of people with diabetes, peripheral vascular disease, neuropathy and trauma, we find a large number of amputees. These people lose their jobs, their routines, their lives. All this is supposed to have a negative effect on amputees and push them into depression. Therefore, we need to help them to go on with their lives normally and not be dependent on society. Where prosthetics were in the 20th century, their main drawback was that they were not part of the human body, and therefore amputees could not feel them, so they must always monitor and focus on the position of the leg; So that they do not fall to the ground as they walk. Active Ankle Prosthesis is the important field in now days it helps amputee to return our partial of their life's. Prosthesis now days doesn't use for cosmetic purpose, but it must do their duty in best ways. In our report, we will talk about gait cycle of ankle (below knee), mechanism of prosthesis & how we implement it in real. Then, we will talk about graphs and equation followed to achieve the gait cycle in right way with respecting the torque and speed of ankle. All that must follow with allowable load of prosthesis corresponding of weight of the man. Then we will talk about control strategy of prosthesis & control circuit & application to detect the patient wants the ankle to be on it.