Abstract: The introduction of porous structures is one of the common and effective means to improve the sensitivity of flexible piezoresistive sensors. However, this method allows the sensor to produce high sensitivity only in a small pressure range, narrowing the detection range of the sensor. In this paper, inspired by the gradient structure of human bones, a flexible pressure sensor with a multilayer gradient foam structure was fabricated by freeze-drying method using thermoplastic polyurethane (TPU) as a flexible matrix and carbon nanotubes (CNTs) as a conductive filler, which was modified by immersing a poly(dimethylsiloxane) (PDMS)/graphene (Gr) mixture to achieve superhydrophobicity. This sensor has a unique gradient pore structure that allows the structure to deform from small pressures to high pressures, enabling simultaneous increases in sensitivity and expansion of the pressure operating range. The test results show that the sensor has a wide detection range of 0~300 kPa and a high sensitivity of 2.609 kPa⁻¹ (0~20 kPa). Not only that, the sensors also have fast response recovery times (210 ms and 230 ms) and excellent stability (withstanding more than 6,000 compression cycle tests), as well as showing high adaptability to complex environments (high and low temperatures, salt spray). The sensor can also monitor human movement, which makes it possible to use flexible pressure sensors in pressure detection, flexible sensing, electronic skin sensors and other applications.