The micro-PECM (Pulse Electrochemical Machining) combining synchronous ultrasonic vibration is proposed as a new technology for to solve the difficulty machining problems of conductive hard and tough materials. The feasibility of micro-PECM combining synchronous ultrasonic vibration is studied. The synchronous way is analyzed; the synchronous electrical circuit is designed and made. The synchronous electrochemical micro-machining system combining ultrasonical vibration are built and improved，which machining parameters can be adjusted in a wide ranges, and the synchronous target of the ultrasonical vibration with the voltage of micro-PECM can be realized. The micro-machining electrodes are manufactured in different sections and sizes by combined electrical discharge machining. The mechanism tests of micro-PECM are carried, which kentaniums （YBD151、YG8）and stainless steel are machined and the results are analyzed and discussed. Contrast with the single micro-USM, the micro-PECM combining ultrasonic vibration has high productivity, good machining accuracy and surface quality; furthermore, its cathode wastage is low. The micro-PECM combining synchronous ultrasonic vibration has the best machining precision and surface quality.