The formation and the stability of the sequence of odd and even gap solitons in self-focusing photovoltaic-photorefractive crystals are studied. These gap solitons only exist in semi-infinite gaps, and their existence domain decreases with the increase of their orders. The gap solitons with higher order occupy more lattices. The energy flow value of these gap solitons increases with the increase of propagation constant. Given a propagation constant, gap solitons with higher order have higher energy flow value. For high-order interphase solitons, the intensities of side lobes are larger and the intensities of the middle lobes are the same. The intensities of side and middle lobes can be controlled by changing the propagation constant. The stability of these gap solitons is investigated numerically and they are proved to be stable.