For fabricated steel-concrete composite beams composed of concrete slabs with reserved post-pouring holes and steel beam with arranged discrete shear connectors， the interface slip distribution theory of fabricated steel-concrete composite beam with discrete interface shear connection is studied. Based on the beam deformation theory， fabricated composite beams with discrete shear connection are divided into shear connection area and non-shear connection area and the interface slip differential equations are established respectively based the displacement continuity and deformation coordination conditions. The interface slip distribution expression of intermittent shear connection composite beam are formulated， and the analytical expression of interface slip distribution under concentrated load and uniform load are solved. Through comparing with the existing slip distribution equation of continuous shear connection composite beam and the measured data of fabricated composite beam test， the slip distribution algorithm is verified. The influence of various parameters on slip and deformation of fabricated composite beams is analized with the parameters as the height ratio of concrete slab to steel beam， the shear connection degree and the clustering degree （an index reflecting the degree of bond clustering， defined as the ratio of the number of shear connectors in a （row） reserved hole to the number of shear connectors in the beam）. The results show that the interface slip decreases with the increase of the shear connection degree， and increases with the increase of the height ratio and the clustering degree； the larger the clustering degree， the more uneven slip distribution， and peak value appears in the non-shear connection area.