Objective To explore the plantar pressure and surface electromyography (sEMG) parameters during human stair walking, so as to provide theoretical support for foot structure design of dynamic walker, selection of power element and distribution of installation location. Methods Ten healthy young males were recruited to perform stair walking trials, respectively. The motion capture system, plantar pressure system and surface myoelectricity acquisition system were used to collect plantar peak pressure, trajectory of COP(center of pressure) and sEMG parameters of lower limb muscles at the same time. Results Compared with level walking, the percentage of stance time in the whole gait cycle increased during stair walking. The peak pressure of forefoot area increased during stair ascent, while the peak pressure of toe area decreased during stair descent. During stair walking, rectus femoris, biceps femoris, medialis and lateralis gastrocnemius played a main role in maintaining the stability of human body. Conclusions The plantar pressure distribution should be fully considered for foot structure design of dynamic walker and the function of main muscles should be considered for selection of power element and distribution of installation location.