Abstract: How to develop an FEA-based dynamic model of spindle assembly was investigated. The change in the central angles of equally and circularly arranged bearing supports of spring-damper elements around the spindle assembly has so small influence on FEA that the FEA-based dynamic model can be developed via developing a rational spindle-support model with those spring-damper elements. Exemplified with the CKS6125 NC lathe manufactured by Shenyang No.1 Plant of Machine Tools, a simulation was done to analyze dynamically the spindle assembly. And the dynamic performance tests of the spindle assembly verified the feasibility of the FEA-based model by experiments, after analysis and evaluation on its dynamic and the convincibility of FEA results.