On crank compound lathe, the way of followup cutting is used to process crankshaft connecting rod with followup cutter rest. It possesses many advantages. The cutter rest exists inertia force and inertia moment in high speed rotation processing if it is not designedor balanced well, affecting the processing efficiency and precision seriously. A new method of increasing counterweight block to carry on the dynamic balance to the cutter frame was proposed. The tool rest threedimensional model was established and then induced to ADAMS. The counterbalance quality was optimized and good effect was obtained.It provides a kind of new method for the tool rest dynamic balance design.