Provided are a hip mechanism and a portable power-assist device, wherein, the hip mechanism (23) includes an upper hip arm (2311), a lower hip arm (232), a first pulley (2312) and a second pulley (2313); the lower hip arm (232) and the upper hip arm (2311) are rotationally connected; the first pulley (2312) is rotatably mounted on the upper hip arm (2311); the second pulley (2313) is rotatably mounted on the upper hip arm (2311); wherein, when a cable (12) is arranged, the cable (12) is introduced from the upper hip arm (2311) and passes around the first pulley (2312), leaves the first pulley (2312) in a tangential direction and then gets into the second pulley (2313) in a tangential direction, after passing around the second pulley (2313), the cable (12) leaves the second pulley (2313) in a tangential direction, and is derived from the lower hip arm (232) to bend the cable (12) into an "S" shape, when the cable (12) performs the tightening action, the cable (12) applies force to the upper hip arm (2311) and the lower hip arm (232), such that the upper hip arm (2311) and the lower hip arm (232) relatively rotate. The hip mechanism can increase the transmission speed of the cable, reduce the wear of the cable, and increase the life of the cable.L'invention concerne un mécanisme de hanche et un dispositif d'assistance électrique portable. Le mécanisme de hanche (23) comprend un bras de hanche supérieur (2311), un bras de hanche inférieur (232), une première poulie (2312) et une seconde poulie (2313) ; le bras de hanche inférieur (232) et le bras de hanche supérieur (2311) sont reliés en rotation ; la première poulie (2312) est montée rotative sur le bras de hanche supérieur (2311) ; la seconde poulie (2313) est montée rotative sur le bras de hanche supérieur (2311). Lorsqu'un câble (12) est agencé, le câble (12) est introduit à partir du bras de hanche supérieur (2311) et passe autour de la première poulie (2312), quitte la première poulie (2312) dans une direction ta