Abstract: With the largest automobile production and best automobile sales around the globe, automobile mould processing capacity is far from being adapted to the needs of the car replacement in China. The milling quality of high-grade car key covering parts mould still can not meet the design requirements. The analysis of hardened steel mould of car large cover milling characteristics and difficult points shows that the modelling and simulation of milling process analysis, processing system dynamic characteristics, the milling stability analysis, the development of cutting tools for automotive covering parts hardened steel mould milling, free surface NC programming technology and process planning are the keys of automobile mould processing. Summarized the status of research in these areas as well as explore the car cover milling hardened steel mould remains to be the further problem. Put forward some suggestions for future research directions.