The high-order collinear and non-collinear quasi-phase matching harmonic generations were realized in a two-dimensional periodically poled LiNbO3 wit h square lattice by tuning the input wavelength. The output spots lay at different symme tric positions with respect to the input beam of picosecond pulse, and the relat ive intensities of spots at certain wavelengths were measured. The high-order no nlinear harmonic processes were also realized by tuning the input angle. The exp erimental and theoretical results are in good agreement with each other. Our stu dies might be beneficial to the development of optics integration and compact de vices.