In order to supply laser-light-source which owns the trait of high stabilization of frequency beat-wave interferomete mechanism of thermal frequency stabilizing of double-longitudinal mode was studied. Based on the mechanism, the length of laser tube was controlled by controlling the discharging electrical current of laser as mainly controlling way and using advanced faradic way as little controlling way, which is a original creation. The fuzzy PID controller was designed to stabilize laser frequency based on the fuzzy controlling theories and expert systems, which doesn't need to found the mode of researched objects. The fuzzy PID controller has a quit adaptive ability for time lag, non-linearity and timeliness. The experiment results of the frequency stabilizing system demonstrated that the precision of frequency stabilizing has little change, but the time of advance heating is obviously shortened and the ability of anti-jamming obviously strengthened. Even if a strong jam acts on the system, it also can soon come back after getting ride of the jam.
