Abstract: In this work, the graphene (Gr) and hydrochloric acid (HCl) doping polyaniline (PANI) as conductive filler were loaded on the flexible polyurethane (PU) fabric by soaking and in-situ polymerization, respectively. Then the Gr/fabric (GF), PANI/fabric (PF) and Gr/PANI/fabric (GPF) flexible strain sensors were fabricated. The structure and strain sensing performance of the various sensors fabricated under different conditions were systematically studied. When PANI with 1.5 M doping and 0.5 mg/mL Gr dispersion solution were used to modify the fabric, the as-prepared GPF has the best comprehensive sensing performance. This is benefited from the significant synergistic effect of the PANI and Gr. Compared with the PF, the GPF has higher sensitivity (15.96 at 50% strain) and faster time response (350 ms), as well as wide strain range (0% ~100%) and excellent repeatability (1 000 cycles). Although the sensitivity of GF is higher (69.7), the repeatability is poor than that of GPF. In addition, the GPF sensor has been successfully used to monitor human motion and physical behavior, showing a good application prospect in the fields of artificial intelligence and wearable devices.