The optimal design of hexagonal chuck clamping force sensor size was realized by using ANSYS, which improved the sensitivity of the sensor. A reasonable diameter ratio between the inner circle and the inscribed circle was obtained, to make the tensile and compressive strain value, measured by the resistance strain gauges, maximize and close to each other. The influence of the centrifugal force on the sensor itself was determined in the case of high-speed rotation. The results show that the size optimization based on ANSYS optimization function is convenient and feasible. It provides a new method for the design and analysis of chuck clamping force sensor.