The utility model relates to an electro-hydraulic servo horizontal tension tester which is characterized by comprising a force bearing frame, a counterforce frame assembly (7), a movable tailstock vehicle body (6), a jaw clamp (8) and a servo oil source, wherein the force bearing frame comprises two symmetric guide rails (1) which are in parallel, an oil cylinder base (2) and a bracket (3); bolt locating holes are formed in the guide rail (1), the movable tailstock vehicle body (6) slides along the guide rails (1) and fixed in the bolt locating holes, the oil cylinder base (2) is connected with the guide rails (1) at two sides through bolts, the counterforce frame assembly (7) is arranged in a middle hole of the oil cylinder base so that a force carrying frame is formed, the bracket (3) is arranged below the guide rails (1), the jaw clamp (8) is arranged in the movable tailstock vehicle body (6), the counterforce frame assembly (7) comprises a higher-power oil cylinder piston, and the movable tailstock vehicle body (6) comprises a lower-power oil cylinder piston.