Steel columns of square or circular hollow section are being increasing used as column in steel frame systems. When lateral forces are applied to the structure, such as during an earthquake loading condition, columns usually are acompanied with sidesway(the top of a beam-column deflects relative to its bottom, this type of deflection is often called "sidesway"). It is the main purpose of this paper to experimental evaluate the strength and deformation capacity with $P{Delta}$ effects of square and circular hollow sections steel beam-columns subject to sidesway by the monotonic loading tests.