In this paper, the morphology of micro-holes on PMMA thin plate manufactured by excimer laser is studied. The influence of laser pulse number on the micro-hole depth is firstly analyzed, and the influence of laser pulse number, laser single pulse energy and laser pulse frequency on the micro-hole taper is further explored. Drilling efficient was observed by optical microscope and SEM. It was showed that in a certain range, the pore depth increases linearly with the number of laser pulses, while the micro-hole taper decreases linearly with the number of laser pulses, and the micro-hole taper decreases linearly with the laser single pulse energy, All the effects are significant. Meanwhile, the laser pulse frequency has no effect on the micro-hole taper. By selecting proper number of laser pulses and low single pulse energy properly, a conical micro- hole with good quality can be obtained with a large depth and a certain taper.