In this article, a new variational pansharpening method based on kernel estimation and regional extended low rank is proposed, which aims to generate a high resolution multispectral (HRMS) image by fusing the panchromatic (PAN) and multispectral (MS) image. First, an estimated blurring kernel is generated for the spectral constraint term, which can build the relationship between the MS and HRMS image more accurately and improve the spectral quality of the HRMS image. Second, a spatial constrain term is designed by adopting the proportional relationship of the PAN and HRMS image in gradient domain, which preserves the geometric information of the PAN image well. Third, according to sensor imaging principle, a prior constraint term is proposed based on regional extended low rank, which can improve the spatial clarity of HRMS image. The above three constraint terms are combined to form the proposed variational pansharpening method, and the ADMM method is applied for solving it. Finally, experiments show the effectiveness of the proposed method through comparing with other state-of-art pansharpening methods.