Abstract: The wall of secondary gas flow distribution pipeline in primary nozzle blade will be heated during CW chemical laser operation. Effects on flow field characteristics of distribution flow pipeline with hot wall boundary under conditions of single end or double ends gas supply were analyzed based on three-dimension computational fluid dynamics methods. The hot wall boundary makes the total temperature of general pipeline higher and higher along the direction of main gas flow movement, and the total temperature of branch pipeline inlet goes up simultaneously, which results in corresponding decrease in mass flow rates of branch pipeline outlets. The fluctuating amplitude of mass flow rates of branch pipeline outlets with hot wall boundary is bigger than that with adiabatic wall boundary, and t