A dynamic characteristic optimization method of feed system based on improved Kriging metamodel was proposed. On the foundation of dynamic model derivation of screw-nut assembly and accurate multi-flexible body dynamic model of feed drive system, the dynamic characteristic of feed system was optimized by taking the Kriging metamodel based on the trust parameters update with the assessment of tool motion (maximum ratio of vibration acceleration), which adopted the column as the design object under the condition of assembly. The optimization result showed that both the structure of column and dynamic performance of feed system from motor to tool were improved.