The critical speed of spindle directly affects the performance of spindle,such as speed,accuracy,vibration and life,which is the main content of spindle dynamic design.The calculating methods of critical speed which include finite element method,transfer matrix method and so on have their own advantages and limitations.The three kinds of calculation method of spindl〖BF〗e’s〖BFQ〗 critical speed were introduced respectively and the key processing steps were illustrated.After comparing the results,the three methods applicable cases were summarized.It provides reference for structure design and performance improvement of spindle.