This paper proposes a high performance electro-hydraulic force transmission method for force control of elbow-joint rehabilitation exoskeleton robot. Exoskeletons are external structural mechanisms that are designed to be mounted on human body so as to support or enhance its physical abilities. Heretofore, they have been considered in several applications such as rehabilitation medicine, military or industry. However, force control methods for these robots still remain a very attractive topic for researchers because of the difficulty to detect motion intention of the operator. In this paper, we propose to connect two syringes through a water tube in order to achieve force transmission between a remotely-located electromagnetic motor and the exoskeleton robot. High force control performance can thus be achieved by the electromagnetic motor while backdrivability is ensured by symmetry of the hydraulic transmission. A theoretical model of the transmission system is proposed and the validity of the proposal is verified experimentally.