In order to provide continuous electric powers to micro systems by using micro rotational generators as power sources,the design approach, fabrication technique and test method of a micro rotational generator were researched. Firstly, a model of three-phase and permanent magnet synchronous generator with a rotor and a stator was designed. The formulas for air density and induced Electromotive Force(EMF) were given by a magnetic circuit analysis and main design parameters of the micro generator were determined. Then,Finite Element Analysis(FEA) was used to analyze the model to obtain the waveform of induced EMF. Furthermore, the precise machining technique was used to fabricate the components of the rotor and stator and to assemble to a micro generator with a size of (Φ7×2) mm3. Finally, micro generator was tested in variations of air-gap thickness and rotation speed. Experimental results indicate that with a air-gap thickness of 300 μm and a rotation speed of 10 kr/min,the induced EMF in one phase is 26.2 mVp-p; when symmetrical loads of 0.23Ω are connected to the generator, the sum of output power is 357.3 μW. Compared to the FEA results, the micro generator shows an ideal output,which means that the generator may be used in micro systems as the power sources.