As the main component of a building, the floor slab is not only a load-bearing element, but also an enclosure structure, and plays an important role in the structural system. The floor slabs in prefabricated building systems should not only meet safety and enclosure requirements, but also facilitate construction and meet the requirements of standardization, batch production, and systematic production, in order to achieve true assembly. Although the prefabricated composite floor building system has developed rapidly, there are still many pain points and difficulties in the construction process, and the construction quality is uncontrollable. For example, there have been many problems with the forming quality of the post cast slab strip of the composite slab. This article is based on the Shimao Ten Mile Star River project, and conducts a special research and discussion on the analysis and control of the current quality status of precast composite panels and post cast strip forming. It provides a solution to the key and difficult points of post cast strip construction process control, in order to provide reference for similar projects.