In this paper, we consider the nonlinear elliptic equations on rectangular tori. Using methods in the study of KAM theory and Anderson localization, we prove that these equations admit many analytic solutions.Remark 1.2. Regarding the rectangular tori, there have been plenty of results on the study of Schrödinger equations on rectangular tori. Bourgain [4] firstly addressed the question of Strichartz estimates for Schrödinger equations on tori. In [11], Bourgain carried out the study