Proprioceptive neuromuscular facilitation (PNF) technique combines both passive and active stretching and significant improvement on muscle strength and coordination has been reported. Therefore PNF technique will be an excellent candidate as a more effective intervention strategy in stroke rehabilitation. The goal of this study is to develop a motorized device which could successively implement PNF hold-relax technique on the ankle joint. The motorized device consists of a servo motor, an inline gear box with a 25:1 gear ratio which increases the loading capacity of the motor up to 50 Nm, one uniaxial torque sensor to register the torque signal. The motor is controlled by a motor drive using speed mode in which both speed and direction of the motor rotation could be modulated. National Instrument PCI6221 M Series data acquisition card was used for data acquisition and motor control. A custom graphical user interface (GUI) written in LabVIEW is used to set testing parameters including speed, ankle range of motion and display testing results in real time. Preliminary study showed that PNF technique can be successfully implemented using the developed motorized ankle device interfaced with the GUI. It is expected that the motorized facilitated ankle intervention will be more effective in increasing ankle joint range of motion and neuromuscular function. It will be a promising intervention for treating spastic joint in stroke survivors.