Unlike traditional laser drilling, the bottom-up drilling of transparent materials involves passing the laser through the material, focusing on the lower surface of the material, and removing the material from the bottom to the top layer by layer. Based on lasers with different pulse widths, this study investigates the mechanism of bottom-up drilling of glass materials. It is found that in addition of ultrashort pulse laser, the nanosecond laser can also achieve bottom-up drilling. Furthermore, it can achieve zero taper drilling. The efficiency of bottom-up drilling decreases with the decrease of pulse width, and the cut efficiency of lasers with pulse width from 2 ns to 50 ps is still higher than that of ultrafast laser. This result differs from the result of general top-down processing, which is attempted to be explained herein.