In order to solve the technical problem of dense micro grooves on the surface of xenon lamp tungsten anode, a method of electrochemical discharge machining (ECDM) of micro grooves on pure tungsten at low conductivity electrolyte was proposed, and RC power supply was applied into the process. The characteristics of ECDM with different electrolyte under RC power supply were studied. Firstly, the polarization curves of pure tungsten materials under different electrolytes were measured by electrochemical workstation, and the open circuit potential at different electrolytes was analyzed. In order to study the influence of the bubbles distribution during the processing, the bubbles formation and distribution in the machining area under different experimental conditions were observed by high-speed camera. Finally, the process of ECDM of micro-groove on the surface of pure tungsten rod was carried out with self-developed test device. The effects of electrolyte type, conductivity, rotational speed and inter electrode voltage on the machining characteristics were analyzed. Under 50μS/cm NaOH solution with an inter electrode voltage of 60V and a rotating speed of 500r/min, the micro groove with width is 50.97μm and the depth is 17.31μm was obtained by ECDM.