To obtain a lower story height and reduce the weight of building structure, the void slabs are proposed. It gives a lot of advantages, since it can make a long span and decrease the $CO_2$ emission by reducing the self weight of the slabs. To improve the construction and performance of void slabs, the new system is developed by combination with the prestressed half PC slabs system. In this study, flexural test was performed to estimate the capacity and analyze the behavior of void slabs with prestressed half PC. A total of 4 full scale specimens were producted. From the results of this test, the flexural strength of void slabs with prestressed half PC had similar behavior with solid slab. And in the comparison of the flexural stiffness, the void slabs had a little lower capacity. However, the yield stiffness of the test results were larger than the predicted one by the current design code. The developed void slabs with prestressed half PC, therefore, can be designed and evaluated by current design code safely.