Developed a device used to assist workover rig in lifting stuck tubing strings from the well during workover treatment, it can create well economic benefit for oil field. The device adopts remote hydraulic control, which is safe and reliable. The structure and work principle of the device is illustrated. The jam release device is mainly made up of hydraulic cylinders, hydraulic pump and hydraulic control valves. With the coordination between lifting hydraulic cylinders and hydraulic slips, the device can lift tubing strings from the well. The important loading unit of the device is analyzed by finite element. The working pressure is made from 5MPa to 20MPa, corresponding to lifting force range of 229kN to 915.6kN, which can meet the jam release force in workover treatment.