According to the long cantilever and non-rigid characteristic of long cantilever coordinate measuring machine, the detailed analysis on the dynamic forces sources of the measuring machine was studied. The influences of the dynamic forces on the measuring error of CMM, and the additive dynamic error sources of the probe were investigated respectively. The conclusions that the additive dynamic error of the CMM probe had three-dimension character and the additive dynamic error in each dimension related to the vibration characteristic of the guide strip system were obtained. The mathematics model of vibration in the group system composed by the cantilever and the measuring staff was deduced subsequently. Based on the model, the corresponding means was adopted to control the vibration. The experimental results proved that the control means is valid and suitable.