The second order nonlinear frequency conversion processes in nonlinear photonic crystals (NPhCs) possess abundant phenomena. It can realize specific modulations of the second harmonic generation based on its different phase matching conditions, which has a great potential research value. In this research, the nonlinear effects at one-dimensional NPhC boundaries, which actually form nonlinear metasurfaces are demonstrated both theoretically and experimentally. Modulated by a periodic χ^(2) structure, the nonlinear Snell’s law is generalized turning into a form that is similar to that in linear metasurfaces, achieving anomalous refraction and reflection with multiple-order second harmonics. Furthermore, a potential method utilizing submicron periodic χ^(2) modulated metasurfaces to realize nonlinear over-reflection is proposed from the generalized nonlinear Snell’s law.