This paper presents in-process compensation methodology to eliminate cutter runout and improve machined surface quality. The cutter runout compensation system consists of the micro-positioning mechanism with the PZT (piezo-electric translator) which is embeded in the sliding table to manipulate the radial depth of cut in real time. For the implementation of cutter runout compensation methodology. cutting force adaptive control was proposed in the angle domain based upon PI (proportional-integral) control strategy to eliminate chip-load change in end milling process. Micro-positioning control due to adaptive acuation force response improves the machined surface quality by compensation or elimination of cutter runout induced cutting force variation. This results will provide lots of information to build-up the precision machining technology.