Based on the analysis of micro electrical discharge machining (micro EDM) principle, the process conditions of micro EDM deposition has been obtained. Micro EDM deposition is a new EDM method, in which the process conditions includes selecting air as working medium, short pulse duration, long pulse interval, low discharge current and setting the tool electrode as anode. In micro EDM deposition experiments, two types pulse generators of transistor type and RC type are applied respectively. The characteristics of discharge waveforms using each type pulse generator are researched. Results show that both two types pulse generators can be applied in the micro EDM deposition process. The transistor type is easy to obtain the same single discharge energy, but short circuit will damage the deposited material. While RC type can adjust discharge energy according to the discharge gap state, which is well used in micro EDM deposition process with the high deposition rate.