In order to fabricate 3D metal microstructures, a combined machining process based on UV-LIGA and micro Electrical Discharge Mechining(EDM) technology was proposed. Firstly,a quasi-3D metal microstructure was fabricated by UV-LIGA technology,and then a 3D metal microstructure was fabricated by micro-EDM. A 3D nickel mold with the local trapezium protrusion and taper groove was fabricated by this method and the sizes of the trapezium protrusion and taper groove were given in detail. Meanwhile, the influence of micro-EDM discharge parameters on the surface roughness was analyzed. The results show that the surface roughness is 0.08 μm, when the operating voltage and nominal capacitance are 65 V and 100 pF respectively. The research results demonstrate that the 3D metal microstructure can be fabricated by this method and the surface roughness will decrease by reducing the operating voltage and nominal capacitance.