This article mainly studies a recyclable fully assembled steel-concrete composite beam, which is composed of several precast concrete slabs and a steel beam through a new type of shear connector (hereinafter referred to as "fastener"). And the fastener is fixed on the steel channel beneath the concrete slab. Moreover, the shear force between the steel beam and the prefabricated concrete slab is transmitted through the friction between those two. In order to study the flexural performance of this new fully assembled steel-concrete composite beam under static load, 6 sets of full-scale specimens were subjected to four-point bending tests under simply supported conditions. The 6 sets of test pieces are all partially shear connections, including 5 groups of recyclable fully assembled steel-concrete composite beams and 1 group of cast-in-place composite beams with studs as shear connectors. The main variable parameters are the number of precast concrete floor slabs and the distance between loading points. The test results show that the composite beam exhibits a certain combination effect under monotonic load. The larger the number of prefabricated plates, the lower the initial stiffness of the specimen, but it has no obvious effect on the ultimate flexural capacity of the specimen. The length change of the pure bending section has no significant effect on the initial stiffness nor the ultimate flexural capacity of the specimen.