Currently, the Off-Site Construction (OSC) construction method, which emphasizes the minimization of field work, is being emphasized at construction sites due to the lack of construction skilled manpower, extreme weather, and the Severe Disaster Punishment Act. In this study, we developed a stacked PC modular, which is a method of stacking PC modules, and solved the lifting problem by reducing the weight of the unit module, which is emerging as the biggest disadvantage of PC modules, to around 20 tons. For the connection between modules, structural safety was secured through repeated history tests of the wall and slab connection. Walls and slabs satisfied all statutory fire resistance times through fire resistance tests, and residential performance was evaluated to be satisfactory through mock-up demonstration. The developed PC modular has been applied to the construction of commercial houses, detached houses, shopping malls, churches, etc., and has design results for many buildings such as dormitories, detached houses with 4 floors or more, and resorts, so it is expected that an atmosphere of revitalization of construction methods will be created.