“…(2013) to find the solution of generalized Lane-Emden equations in [1] and it has been applied in 2016 by İnç, M., Korpinar, Z. S., Al Qurashi, M. M., & Baleanu, D. to find the approximate solutions of some nonlinear equations [6]. It was also applied by Manaa, S. A.,& Mosa, N. M. in 2019 to solve the Kaup-Boussinesq System [8] and by Modanli, M., Abdulazeez, S. T., & Husien, A. M. in 2020 to solve "pseudo hyperbolic partial differential equations with nonlocal conditions" [9]. In this paper, the Residual Power Series Method (RPSM) [1], [6], [8] and [9] is applied to solve Klein-Gordon Schrödinger (KGS) Equation.…”