It is great difficult to manufacture a closed integral component due to its poor processing accessibility caused by complicated structure of air flow channel between two blades, especially the large bending and twisting degree in the channel as well as its component materials of high strength alloy. To solve this problem, several key technologies of electrical discharge machining (EDM) are discussed, such as division of the processing zone among the blades, shaped electrode and its motion trajectory design, process benchmarking unification, process parameters selection and optimization,simulation of EDM process and so on. On top of this, typical closed integral components are studied and manufactured. It is shown from the experimental results the above-mentioned technologies enable numerical control EDM technology to realize precise and reliable manufacture of closed integral components.