The micro-blind hole technology of flexible circuit board is a key part of high density interconnection fabrication process. In this paper, a 355 nm UV laser was used to drill the double-sided flexible copper clad plates. The effects of UV laser power and scanning speed on the morphology and quality of blind holes of two kinds of flexible coppers (electrolytic copper and calendered copper) were studied. It is found that the laser power and scanning speed have direct effect on the quality of the blind hole. Results show that when the laser power is 4.5 W and the scanning speed is 50 mm/s for calendering copper, and the laser power is 5.5 W and the scanning speed is 150 mm/s for electrolytic copper, the quality of the blind hole is the best.