The onedimensional nonlinear photonic crystals containing defects that are embedded in air are investigated. However, attributed that the reflective second harmonic wave is so strong that it can not be ignored, the slowly varying amplitude approximation is not applicable to such a system. The paper presents a general solution of second harmonic generation without adopting the slowly varying approximation when the incident light is obliquely launched upon the onedimensional inhomogeneous systems. The result shows that the wavelengthes corresponding to the defect modes shift to the shortwavelength with the increasing angle of incidence. The broadened band width second harmonic generation with high conversion efficiency can be achieved by modulating the angle of incidence of fundamental wave. Furthermore, this method can be applicable to any onedimensional inhomogeneous systems and the conversion efficiency of second harmonic generation can be easily and conveniently calculated.