In this work, we report a highly sensitive and flexible capacitive pressure sensor based on a porous dielectric matrix containing multi-walled carbon nanotubes (MWNTs) as conductive fillers. Porous dielectric matrix containing conductive fillers has a high resolution because the conductive fillers increase dielectric constant of the matrix and make big difference of dielectric constant between micro-pore in the matrix and matrix itself. This difference leads to a high sensitivity. Additionally the output signal of the pressure sensor shows little variation under different environment disturbances, such as dynamic pressure inputs, temperatures, and different air humidity levels. Furthermore, a robot-arm system, with the ability to move a soft material, is constructed to demonstrate the practical applications of the pressure sensor by using a pressure feedback control.