A reflective metamaterial polarization transformer (RMPT) is proposed with closed fish-scale structure for high efficient cross-polarization reflection. The maximum efficiency of cross-polarization reflection for normal incidence is 97.2%. The RMPT maintains good performance for incident angles up to 25, and the RMPT is not restricted to a specific polarization state of the incident wave. Furthermore, the designed RMPT shows excellent structural tunability by optimizing the structural parameters, which makes it userfriendly. (C) 2017 Elsevier B.V. All rights reserved.