The invention discloses a 
laser frequency stabilizing method and optical 
system for improving performance of an 
optical pumping cesium beam 
atomic clock. According to the method, a detected 
fluorescence signal of the 
optical pumping atomic clock is divided into two paths, one path of 
fluorescence signal is input into a 
microwave cavity of the 
optical pumping atomic clock through a feedback deviation correction loop, and the other path of 
fluorescence signal is input into the spectrum input end of a 
laser frequency stabilization module; 
laser output by a laser device sequentially passes an 
isolator (1), a 
delay wave plate (6) and a polarizing 
beam splitter (7), and is divided into two beams, one beam is used as detection light and enters a light pumping atomic 
clock detection area, and theother beam is focused by a lens, enters an acousto-optic modulator (9) for 
frequency shift output and then collimated into parallel light by a lens, and the parallel light is used as pumping light andenters a light pumping atomic 
clock pumping area. According to the invention, only one AOM device is added, and two sets of complex saturated absorption 
spectrum light paths and one laser are omitted, so that the 
system complexity of the whole 
clock is reduced, the cost is reduced, and the 
system reliability is improved.