Abstract: Since its low lateral stiffness, the inter-storey drifts of an un-braced stee-l frame building usually become key factors in structural design. Adding bracing to the structure is an effective measure which can improve the overall lateral stiffness and decrease the stee-l consumption. The mult-i storey and high-rise braced stee-l frames are taken as an object, through calculating the top displacements of the stee-l frames braced by different types and layouts of bracing, it studied the influence of bracing kinds on the lateral stiffness of the mult-i storey and high-rise braced stee-l frames. The results shows that, for different kinds of bracing, the lateral stiffness of a steel frame with bracings on middle spans is higher than that on side spans or other spans; for the same layouts of bracing, either centrically braced frame, or eccentrically braced frame, in the facets of lateral stiffness and economy, herringbone braced frame is better than single sway rod braced frame.