Abstract: The excimer laser refractive surgical instrument can be used to correct myopia, hyperopia , astigmatism diopter. The laser control in the surgical instrument offers steady laser pulses, it is very important to ensure surgery's safety and stability. In this paper, the composition of surgical instrument is described, and the laser control including the communication between computer and laser device, laser pulse on-off control and gas exchange are detailed. At present, this kind of surgical instrument has been applied to clinical use and obtained very successful results .