The invention provides a left-right turning screw rod stretcher specially used in a metallic plastic deformation and recrystallization test. The stretcher comprises an electric appliance control part, a screw rod transmission part, a mechanic transmission part and an aluminum sheet clamp part, wherein by the rotation of a left-right turning ball screw rod in the screw rod transmission part, a sample, of which both ends are tightly clamped, is outward stretched from the left and the right sides at the same time, and the stretching force is kept stable and uniform during stretching; the stretching size can be controlled to the micrometer level by the accurate step pitch turning angle of a stepper motor, so that the stretching in different deformation degrees can be realized according to thetest requirements; and simultaneously, an assembled displacement ranging rod is connected with a working table of the clamp, so that the stretching distance can be quite accurately measured and displayed, the deflection generated when the sample is stretched can be accurately shown, and the success ratio of the test is improved.