Abstract: A finite element analysis was performed on the Reynolds equation for the gas flow between the two faces of a non-contacting dry gas face seal with spiral grooves (S-DGS) applied to a centrifugal pump for emission control. Thus the deformation of the both faces caused by pressure and contact forces of the S-DGS consisting of a stator ring with different constructions and/or constrictions and its effect on the principal parameters such as seal opening force, flow leakage rate, and gas film axial stiffness of the seal were investigated. The stability of the several seals with different constructions and constrictions was examined. It was found that the face mechanical deformation caused a divergent sealing gap whose value was closely dependent on the construction and/or constriction of the stator ring. Moreover, the face deformation had a slight effect on the seal opening force but great effect on the gas film stiffness. Therefore, it was imperative and feasible to decrease and even avoid the face deformation by selecting suitable constrictions, which hence made it possible to increase the stability of the S-DGS.