The governing equation of gas cylindrical spiral groove is solved theoretically by the coordinate transformation from non-rectangle grid in computational area with complex shape to rectangle grid. The purpose of the transformation is to avoid re-forming grid while the structural parameters being changed. The design parameters that affect the seal performance are proposed. The relationship of these major parameters such as groove numbers and spiral angle to seal pressure is revealed and the optimized result is obtained. Mass experiments are conducted in designed test rig. Experimental results have a good agreement with the calculated ones. In the end, the selecting domain of structural parameters to design gas cylindrical spiral groove seal is concluded for engineering application.