The invention discloses a method for acquiring a pixel scale true value of a remote sensing product. The method comprises the following steps of: 1) acquiring a large-scale remote sensing product; 2)determining an upper envelope line (surface) and a lower envelope line (surface) of the inversion model; 3) constructing a remote sensing product true value calculation model; 4) determining weight coefficients of the upper envelope line (surface) and the lower envelope line (surface); and 5) calculating the true value of the pixel scale of the remote sensing product. According to the invention, aconvex set theory-based remote sensing product pixel scale true value calculation model is constructed; The model does not need to be assisted by matched small-scale priori knowledge, the defect caused by high dependence of an existing method on matched small-scale data is overcome, the cost for obtaining the matched small-scale data is saved, and the implementation process of remote sensing product pixel scale true value obtaining is simple and convenient. The method is suitable for inversion models in various forms, and the universality of the remote sensing product pixel scale true value obtaining method is ensured.