Defocusing effect on the patterns of microlens array imaging photolithography is analyzed, and tolerance of defocusing range of the system is given. Meanwhile, a novel method with simple structure for zooming is proposed, which is able to be used in microlens array photolithography system for zooming. Then the equipment based on adjustment focus method is applied to microlens array imaging photolithography, and experiments are carried out on the microlens array imaging system. At last, it is proved that the quality of patterns fabricated by this zooming method approaches to the optimized image quality of microlens.