[en] A small sample stretcher for in-situ measurement of small angle X-ray scattering (SAXS) was developed, which consists of stretch, transmission, detection and control systems. The basic parameters of the stretcher are: tension ≥ 400 N, 3 mm/min ≤ stretching speed ≤ 50 mm/min, sample length ≤ 30 mm, stroke ≥ 80 mm, and resolution = 50 μm. The stretcher is compact and has low stretching speed and convenient remote control. It is suitable for in-situ SAXS measurements on stretching of carbon fibers, polyethylene and other samples. Such measurement were carried out with high density polyethylene (HDPE) on the SAXS instrument at the 1W2A station of Beijing Synchrotron Radiation Facility (BSRF). The result verified the effectiveness of the stretcher.