The invention discloses an automobile transmission shaft length detection device with an elastic element. The automobile transmission shaft length detection device comprises a base, a sliding rail, a fixed plate, a movable plate, cylinder clamping devices, the elastic element, a motor driving device, a force sensor and a supporting device. The sliding rail is fixed to the upper portion of the base and provided with the fixed plate and the movable plate, the fixed plate is fixed to one end of the sliding rail, the bottom of the movable plate is provided with a sliding block matched with the sliding rail, and the motor driving device is fixed to the sliding rail. The elastic element is fixed to the bottom of the movable plate, one end of the force sensor is connected with a motor head connected with the motor driving device, and the other end of the force sensor is connected with the elastic element. The upper portion of the fixed plate and the upper portion of the movable plate are provided with the cylinder clamping devices for clamping the two ends of a to-be-measured automobile transmission shaft, and the supporting device is arranged on the sliding rail between the fixed plate and the movable plate. The problem that an ordinary motor cannot guarantee force stability in the automobile transmission shaft length detection process is solved, the accuracy of measurement results is improved, and the production cost is reduced.