In order to improve form cutter accuracy in grinding process, a closed-loop control system was designed to accomplish adaptive control of constant force in grinding process. Since it is a complicated dynamic process with severe nonlinear and much stochastic disturbance, fuzzy adaptive controller was used which can adjust parameters online. By measuring grinding force, characteristic information of grinding process was acquired. Regulation factor of feed rate is determined by grinding force ratio, and force deviation and its change rate are used as evaluation indexes. Thus, adaptive control of constant force in grinding process is accomplished. Simulation and tool grinding test indicate that the system has high precision and stability, and reduces cutter error efficiently.