This paper proposes unmanned aerial vehicle (UAV)-reconfigurable intelligent surface (RIS) communication that takes energy efficiency into account in non-terrestrial networks through trajectory optimization of UAV-RIS that jointly considers communication throughput and energy consumption of UAV. The proposed algorithm optimizes the UAV-RIS trajectory, base station beamforming vector, and RIS beamforming vector by appropriately using successive convex approximation, Karush-Kuhn-Tucker conditions.