Abstract: This paper introduced formulas and computed the required blower pressure for the gas-air premixed combustion system composed of Venturi and self operated regulator. Different blow pressure is required for distinct connecting type of the same performance Venturi' and self operated regulator. The required blower pressure for the zero governor type is 43%~115% higher than that for the iso-pressure type. To save power the best connecting type should be chosen which might obtain the highest gas pressure at the self operated regulator outlet.