The invention relates to a control of a passive prosthetic knee joint with adjustable damping in the direction of flexion and in the direction of extension for adapting a prosthetic unit which comprises a lower leg shank and an artificial foot fastened to the prosthetic knee joint to climbing stairs. The method according to the invention comprises the following steps: detecting a low-torque lift of the prosthetic foot, lowering the flexion damping in a lift phase to below a level which is suitable for walking on level ground, increasing, in a time-delayed manner, the flexion damping in a placement and hip straightening phase to a level above a damping of a swing phase control for walking on level ground.
