Abstract: The closed diluted gas cycle chemical oxygen iodine laser (CGC-COIL) was considered as a promising miniaturized laser; however, we havent read any experimental study reports till now. In this study, a simulation experiment setup composed of supersonic nozzle and screw vacuum pump was built, and it was used to study the feasibility and the operation stability of CGC-COIL by means of measuring the inlet and outlet aerodynamic parameters of the supersonic nozzle and screw vacuum pump. The simulation experiments firstly demonstrated the feasibility of this type of laser, and then confirmed the optimal stable operation condition of this type of laser by finding and explicating the phenomenon that a simulation laser cavity pressure inflection point will appear with the increase of the revolving speed of screw pump. The study provides an experimental evidence for CGC-COIL realization and a new technological approach for chemical oxygen iodine laser miniaturization.