Flexible noncontact sensors are of great significance in contemporary applications. Nevertheless, conventional noncontact sensors that rely on metal electrodes have limited flexibility, and their multilayer architectures are likely to experience interfacial delamination during extended use. To tackle these problems, we introduce an all-gel-based flexible triboelectric noncontact sensor, which consists of two parts, i.e., the gelatin/poly(vinyl alcohol) (PVA)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/graphene (G) electrode hydrogel and PVA/cellulose/carbon nanotubes (CNT) triboelectric aerogel. The hydrogel electrode not only features outstanding biocompatibility but also exhibits high conductivity. The triboelectric aerogel demonstrates excellent mechanical properties, such as good elasticity and durability. This sensor can stably output a noncontact current of 1.18 μA, a charge of 18.4 nC/cm2, and a voltage of 3.7 V at a stable state. It can accurately and reliably detect a wide range of human motions, such as elbow bending, knee movement, and running, providing a reliable and flexible approach for human motion perception and facilitating the progress of relevant fields.