Though many studies on the composite effect on steel beam by concrete slab were conducted, study on the composite effect on panel zone is very few. Of course, concrete slab affects not only beam but also panel zone. Concrete slab transmits compressive force under positive bending. Therefore, the loading point moves up to the slab position from top flange, accordingly the effective depth of the panel zone extends upward. Although such an effect of concrete slab on panel zone has been already pointed out, enough study was not conducted. In this study, structural performance of panel zone considering the composite effect is investigated by experimental and analytical approach. At first, cyclic loading test of full-scale partial frame was carried out. Specimen consists of wide-flange section beam, concrete slab and square hollow section column. Elasto-plastic hysteretic behavior of panel zone was acquired as experimental results. Secondary, elasto-plastic analysis by finite element method under monotonic loading was carried out. Parameters of the analysis are existence of concrete slab and orthogonal beam. From both experimental and analytical results, effective depth of panel zone affected by existence of concrete slab is examined.