High-performance flexible pressure sensors are critical to realizing electronic skin and wearable devices. It is the persistent pursuit of researchers to develop more sensitive flexible pressure sensors. Here, we propose a simple and effective strategy to fabricate flexible piezoresistive pressure sensors based on fragmented graphene aerogel (FGA)/polydimethylsiloxane (PDMS) sponges. Using FGA as a conductive filler and NaCl particles as a porogen and blending with PDMS, a composite material FGA@PDMS with a sponge structure was obtained. Then, the composite FGA@PDMS was dip-coated with FGA to achieve the FGA/FGA@PDMS sponge. Finally, the interdigitated electrode was printed as the bottom electrode by the screen-printing process to complete the preparation of the FGA/FGA@PDMS sensor. The results show that the fabricated flexible piezoresistive pressure sensor has higher sensitivity (0–10 kPa, 2235.84 kPa–1), good recovery, shorter response time (∼120 ms), and stable response under 1000 cycles of loading and unloading. Moreover, we investigated the applicability of the FGA/FGA@PDMS sensor as a wearable device and its application in practical sensing. Human motion detection such as arm bending, fingers, and soles of the feet shows that the sensor has good detection ability. The light-emitting-diode series circuit and the bluetooth-based wireless pressure sensor verification prototype system demonstrate the potential of the sensor for practical applications.