Abstract: Due to the defects associated with the warp tension testing system, this paper designs a new testing system of warp tension based on optical fiber force sensor, which contains a force sensor based on F-P optical fiber strain, elastic structure and photoelectric conversion system. APC circuit was used in the light source circuit of the optical fiber force sensor；The APC circuit was made up by two operational amplifiers, transistor and periphery circuit, which adopts backward photorefractive feedback offset control. The calibration test of static state characteristic for optical fiber force sensor indicates that the sensor has high precision. The experiment of test warp tension with the optical fiber force sensor testing system on YC426 jet weaving machine was carried out, and satisfactory results were obtained.