This thesis investigates the vibration suppression of milling machines by suspensions that employ the inerter. First, we obtain the frequency responses of a milling machine, and madel it as a fourth-order suspension system. Second, we apply springs, dampers, and inerters to discuss their individual effects in repressing system vibration. We also measure the cutting acceleration, air pressure, and surface roughness for verification. Third, we design four mechanical networks which are composed of springs, dampers and inerters for optimizing parameters. Last, we set up experiments, and show that the optimization can predict the cutting vibration.