Non-polar a-plane ZnO film grown on (001)LaAlO3 (LAO) substrate has been systematically characterized by employing transmission electron microscope. On (001)LAO substrate, a-plane ZnO film comprises two main orientation types of domains perpendicular to each other. In one orientation type of a-plane ZnO domains, stacking mismatch boundary (SMB) and inversion domain boundary (IDB) form in the coalescence of two domain islands parallel to each other. SMB is composed of m- and r-planes. IDB extends along m-plane. The in-plane growth of a-plane ZnO domains extends along the direction with ∼45°-rotation to [0001]ZnO. The boundaries of two perpendicular a-plane ZnO domains consist of 45°-boundaries and r-plane twin boundaries. The profile of a-plane ZnO domain appears as L-shape.