The invention discloses a hip joint external skeleton power-assisted mechanism. The system consists of a waist bracket, a thigh bracket, a thigh bandage, a middle cover, a back cover, a turntable, a big spring, a small spring, a sliding block, a first connecting rod and a second connecting rod; the waist bracket is fixed on the waist and is used for bearing the whole hip joint power-assisted mechanism; the thigh bandage can fix the thigh bracket on the thigh of a human body; the turntable can rotate along with swinging of the thigh bracket; through rotation of the turntable, the spring can bedriven to perform reciprocating telescopic deformation; and through the action of the spring, energy storage and release are realized in the swinging period of human walking. Through design of a rotating mechanism and an elastic mechanism, the hip joint power-assisted mechanism can assist the human body in walking so as to achieve the power-assisted effect.