The propagation characteristics of two-order soliton are numerically studied in Kerr-type nonlinear medium with transverse periodic modulation of refractive index. It is shown that the periodic modulation will lead to the formation of two fundamental solitons with different amplitudes resulted form two-order soliton’s decay. Further, the fundamental soliton with big amplitude will propagate across the potential well when the incident angle is above a critical value or the modulation depth and period are below a critical value; otherwise, it will propagate across the potential well. However, the one with small amplitude will always propagate across the potential well. Therefore, the special propagation behavior of two-order soliton in optical lattice is expected to show great potential for many applications such as optical calculation, all optical communication and the development of novel photonic devices, both theoretically and practically.