This paper introduces a smart flexible sensor adapted to textile structures，able to measure their strain deformations. A new method is investigated in preparing the conductive polymer composite，which is based on a thermoplastic elastomer（Evoprene）/carbon black nanoparticle composite. The optimization of filler concentration is found by the electrical experimentation. The sensor is then integrated on a thin，lightweight nylon fabric，and the electromechanical characterization is performed to demonstrate the adaptability and the correct functioning of the sensor as a strain gauge on the fabric.