Fabrication process of quartz microlens arrays with different diameters based on photoresist thermal reflow and plasma etch method was introduced. The main process of microlens fabrication, such as reflow and inductive coupled plasma reactive ion etching (ICP-RIE), were studied. Finally, the optimal process parameters were determined, and quartz microlens arrays with diameters from 20μm to 70μm and high surface quality were prepared.