The effects of Kerr nonlinearity on the band-gap structure of one-dimensional ph otonic crystals was investigated. The photonic band-gap in the nonlinear region can be modulated by changing the intensity. It was found that due to the nonline ar modulation, the electromagnetic eigenmodes of cosine function type go into th e linear gap and become soliton-like modes of hyperbolic secant function type. A number of novel soliton-like electromagnetic modes are found in the gap.