Electrochemical micro-machining (ECMM) is a method that utilizes anode dissolution principle to process shaping. In the Electrochemical machining (ECM)of micro-hole, machining precision is an important aspect to measure machining quality of micro-hole. In this paper micro-hole machining is regarded as the research object, effects of many factors such as power supply natures, electrolyte composition, pulse width and pulse frequency on machining accuracy in micro-hole ECM have been evaluated. Research shows that processing accuracy can be improved through using non-linear electrolyte in high frequency, narrow pulse electrochemical machining.