Abstract: A novel top-supporting modular truss system for prefabricated concrete slabs is proposed in this paper. This system can be assembled using standard modular truss units. By embedding bolts in the prefabricated floor slabs， the assembled truss support system can be installed at the corresponding positions on the slabs without the need for bottom supports. A parametric analysis using a finite element model was conducted to investigate the internal force distribution of the truss supports， the mid-span deflection of the slabs， and the damage during the construction stage. From the perspective of bearing capacity， stiffness， steel consumption， and construction convenience， reasonable structural forms and optimal component types were determined for the top-supporting truss system， and a supporting construction technical process was proposed. Research shows that the system is structurally reasonable， safe and reliable， easy to install and dismantle， and consumes less steel， which effectively reduces construction time and costs. Thus， this supporting system holds significant promotion value for practical engineering projects.