Based on the contrast experiments of unbonded prestressed concrete slabs with openings subjected to uniform load strengthened by different methods, this paper investigates and analyzes the appearance and the development of cracks, deflections, bearing capacity of the unbonded prestressed concrete slabs that are with strengthening steel and with hidden beams. According to the experimental failure mode of the slabs, prestressed concrete slabs with openings by yield line theory considering the conditions to enhance the contribution of hidden beam and the strengthening steel. Compared with the experimental data, this paper puts forward some bearing capacity lift-off effect of the slabs under different strengthened methods.