With the expansion of high-end equipments and products, performance tolerance standard of some equipments and products becomes more and more high. In this case, a large number of high performance parts come into being. The machining of these key parts has changed from pure geometric accuracy requirements to performance-geometry integrated precision machining requirements under the premise of taking performance requirements as a primary target. Such high performance parts often have complex surfaces and ultra-high machining accuracy, and consequently use difficult-to-cut materials with supper-hard, supper-brittle or supper-sticky characteristics. Due to the case that the part performance has complex coupled effect with many factors such as part geometry and material, it is rather difficult to manufacture with a high precision when using traditional machining processes, which often lead to high rejection rate, low machining efficiency and particularly out-of-tolerance part performance. For satisfying the requirement of manufacturing industry, a new digital machining way for high performance key parts is presented in this paper. The characteristics and classified system of high performance key parts are described. Then reasons of high product rejection rate using experiential method and connotations of positive digital machining of complex surfaces are subsequently expounded. Key issues and their research statuses, existing problems and solving measures of positive machining technologies are finally discussed in detail. It provides an effective reference and guidance for the establishment of performance-geometry integrated machining principle, method and process technologies, and then as a result to solve the issue of the precision manufacture of high performance parts.