In this paper, the effect of shear studs spacing on the steel plate action in steel concrete composite shear walls is investigated. Shear studs spacing is an effective factor affecting local buckling of steel plate and the level of composite action between steel plate and concrete infill in composite steel-concrete shear walls. Steel concrete composite shear walls consist of thick concrete walls with exterior steel faceplates which serve as reinforcement. The steel faceplates are anchored to the concrete infill using shear studs. In a composite shear wall with enough shear studs, the concrete wall restrains the steel plate and prevents its buckling before it yields. As a result, the steel plate resists the story shear by yielding in shear. The shear yield capacity of steel plate can be significantly greater than its capacity to resist shear in the yielding of a diagonal tension field. In this study, a finite element method is used to investigate the elastic buckling load of a steel plate bolted to one side of a reinforced concrete panel under shear loading. Using the steel plate unilateral buckling coefficients, the maximum shear studs spacing which prevents local buckling before yielding is calculated. Since the main role of a composite shear wall is to provide shear strength and stiffness, the effect of different shear stud spacings on the level of composite action between the steel plates and concrete infill and the development length of a steel concrete composite wall is investigated. Comparing the results with those obtained by AISC 2010, some suggestions are presented.