According to the construction site of Zibo athlete apartment and the relevant standards, the structure constitution of the composite floor system, construction method and the problems that should be paid attention during construction were introduced in detail. Reinforced concrete composite floor system of superimposing box and net beam consisted of small prefabricated components- two reinforced concrete plates locating at top and bottom of the box and the cast-in-site concrete beam. This composite floor system was a whole structure of beam and plate combination, with a continuous box section. The superimposing box undertook the loads action together with the rib beam. The floor system has many advantages such as the industrial prefabricated components, stable construction quality, reduction of labor intensity in construction site and the environmental pollution, and the integral structure.