The invention discloses a reservoir heterogeneity characterization method under a regular development well pattern of horizontal wells. The method mainly comprises steps as follows: establishing a research area construction model to construct a target stratum model; (2) performing simulation to obtain a lithological model based on the stratum model established in Step (2); establishing a reservoir permeability 3D model in sandstone in the lithological model established in Step (3); establishing a virtual vertical well at the wellhead of each horizontal well; extracting stratum hierarchical data and permeability curves of each virtual vertical well; calculating the permeability heterogeneity parameter of a target interval of each well by using vertical well permeability curves in actual drilling and the permeability curves of the virtual vertical wells obtained in Step (6); drawing permeability heterogeneity parameter plane contour line maps to represent heterogeneity characteristics of reservoirs. A more accurate method is provided for carrying out reservoir heterogeneity characterization for oil fields exploited with horizontal wells as the main means.