The invention relates to the field of 
photolithography based on computer-to-plate techniques and provides a photolithographic 
machine exposure system and a control method thereof. The photolithographic 
machine exposure system comprises a 
light source, a light path 
assembly, a photolithographic lens and a substrate, which are connected in sequence. The light path 
assembly modulates the optical 
signal emitted by the 
light source and then outputs the optical 
signal. The photolithographic lens focuses the optical 
signal output from the light path 
assembly onto the substrate to form a 
first light spot. The photolithographic 
machine exposure system further comprises an optical device, a controller and an exposure lens assembly, wherein the controller controls the optical device to emit the optical signal from the 
light source, and the exposure lens assembly focuses the optical signal emergent from the optical device onto the substrate to form a second 
light spot. The 
diameter of the second 
light spot is larger than that of the 
first light spot. The photolithographic machine exposure system adopts the optical device to change the travel direction of the optical signal, adopts the exposure lens assembly to focus the optical 
signal on the substrate to form the large 
light spot, achieves the effect of rapid exposure of the large clear area without affecting the exposure of the fine pattern, and increase the work efficiency of the photolithographic machine.