This paper conducts a study on a precision micro abrasive waterjet (PMAWJ) machining system. A new kind of precision micro abrasive water jet system is designed and tapped. The flux and the flow velocity of the PMAWJ system are tested by experiments. Using the micromachining system, a group of polishing experiments is conducted for two kinds of hard-brittle materials such as silicate glass and silicon nitride. The results show the feasibility and the advantage of the PMAWJ machining system for polishing hard-brittle materials.