The invention relates to the technical field of orthosis devices, in particular to a hydraulic damper for an exoskeleton orthosis device. The hydraulic damper comprises a piston cylinder and a proportional valve, wherein a first oil cavity and a second oil cavity are formed in the piston cylinder, a first piston is arranged in the first oil cavity and is connected with a piston rod, a second piston is arranged in the second oil cavity and is connected with a spring, the spring is connected with the inner wall of the second oil cavity, and the proportional valve is arranged between a first oil way and a second oil way. The hydraulic damper is matched with a walking state of a human body through telescopic movement of the piston rod in the piston cylinder, and the telescoping rate of the piston rod in the piston cylinder is adjusted through the proportional valve, so that piston movement of the piston rod in the piston cylinder can be passively matched with the walking state of the human body, adjustment is performed at any time according to the walking speed of a user, it is kept that the human body walks freely to the most degree, and the stability is ensured.