The ability of mechanosensing is essential for intelligent systems. Here we show by molecular dynamics simulations that a graphene flake on a bent beam exhibits amazing mechanosensing behavior. The graphene flake can perceive the bending gradient of the beam which indeed leads to a gradient of atomic density and produces a driving force on the flake toward the direction of increasing density. We develop also an analytical model to further confirm the mechanism. Our findings may have general implications not only for the potential applications of graphene as sensing elements in nanoscale intelligent devices, but also for the exploration of mechanosensing capability of other two-dimensional materials.