The purpose of this paper is to introduce a design and fabrication procedure for a solid propellant gas generator. Based on this procedure a gas generator was designed to supply the required operating fluid of a controllable flying object’s gaseous actuator of control surface which results of that design is presented in this paper as well. Supplying required pressure during the mission and gas flow rate with expected chemical characteristics are requirements of the design. At first the amount of necessary parameters like flow rate and pressure were specified. Then the design calculations were done according to proposed approach. In order to evaluate the design process and achieved data, a full scale gas generator set was built. Since this study includes specifying a proper formula for solid propellant of gas generator, a lab scale motor was used to qualify the propellant’s characteristics experimentally. After doing tests and comparing the results with output data of gas generator design procedure, convenient consistency was observed. Besides by doing several tests it was found that PSAN as oxidizer, HTPB as binder and chromium oxide as catalyst is a proper composition for solid propellant of gas generator. Finally, covering basic requirements of a solid propellant gas generator such as uniform flow rate and less presence of solid phase and corrosive components in combustion products by means of designed gas generator is an approval to show the validity of presented design method.