Based on the Landau-de Gennes theory, the diffusion of order reconstruction induced by 1/2 wedge disclination in a thin hybrid cell is investigated by the relaxation iterative method. The core structure, the biaxial structure, and the diffusion of order reconstruction as the cell thickness decreases, are explored. The defect structure and the range of order reconstruction do not change when the cell thickness is larger than 15. As the thickness decreases from 15, the defect range broadens along the substrate direction, and the biaxial region as well as the range of order reconstruction also enlarges. When the thickness further decreases to below the critical value of 10, the biaxial region and the order reconstruction range merge into an entire cell, where the planar orientation is abruptly converted into the perpendicular one across the biaxial wall. The results obtained in this paper are important for further studying the regulating effect of topological defect on submicron colloidal particles in nematics.