Abstract: A CO2 laser fluid recycle control system is described in this paper. The used structrure and programmable control means in this system permit not only the accurate control and maintenance of gas pressure substantially constant in CO2 laser but also the automatically adjustment of the fluid exchange volume and the different compositions of supplied mixed fluid according to the laser working sta-tus(CW or Pulse)and its output power.All parameters can be preset before the operation of the laser and can be conveniently,precisely and selectively varied at any time of the operation.