Photonic quantum-well (QW) structures can be constructed by stacking 3 photonic crystals (PCs) with the same photonic band gap and different defect modes. On condition that the defect mode of the PC in the well region is located into nontransmission frequency ranges of the PCs in the barrier regions,the confined photonic state appears and can completely transmit through the structure by tunneling. However,its transmission will be strongly prohibited due to vanishing of the photonic QW induced by shifting the defect mode frequency of either of the PCs in the surrounded regions to that of the middle PC. Switching and narrow band filtering can be realized simultaneously with the structure. The theoretical calculation has been carried out by transfer matrix methods.