A simple weighted-density approximation (SWDA) based on both local and bulk densities at the level of the first functional derivative of the system free energy is proposed. Its applicability to highly inhomogeneous hard-sphere fluid is verified by using Percus＇ idea to investigate the equilibrium structure of a uniform hard-sphere fluid. Then, the SWDA is used to investigate the density profiles of hard-sphere fluid in spherical cavity, its prediction is compared favorably with simulation data.