The utility model discloses a test device of electric eddy -current damper rotational damping coefficient relates to suspension cable vibration control technical field. The top of the device's tester support is fixed with the tester that is used for testing rotation torque and rotational speed, and the top of motor support is fixed with motor and speed reducer, and motor and speed reducer are through driving the mobile core hub connection, the central level of tester is provided with the tester dabber, the one end of tester dabber through first shaft coupling with drive the mobile core hub connection, the other end has the damping axle through the second coupling joint, the outside cover of damping axle has two location retaining ring and no line strain testers that are fixed in the damping axle, and no line strain tester is connected with three set at least three -dimensional foil gages, and this three -dimensional foil gage is fixed in the surface of damping axle to along damping axle circumference evenly distributed. The utility model discloses not only simple structure, easily operation, and the measuring accuracy is high.