The formation of the spatial solitons in the quadratic nonlinearity χ^((2)) media by cascading second harmonic generation (SHG) in quasi-phase-matched (QPM) sample is studied on the basis of nonlinear Schrodinger equation (NLSE). When the solitary wave propagates in the QPM media, it formed optical wave-guides through cascading χ^((2)) effect called self-induced soliton wave-guide. Transverse refractive index distribution of the self-induced soliton wave-guide of fundamental and SHG wave is obtained by cascading process. Analysis of guided-mode of such self-induced soliton wave-guide is first proposed to our knowledge. Because the power needed for forming the spatial solitons in cascading process is much lower than that inKerr media, this kind of self-induced soliton wave-guide shows potential applications in all-optical signal process.