In this research, dehydrogenation properties of several hydride-hydroxide systems containing KH and KOH have been evaluated. Six types of hydridehydroxide systems (KH-M[OH] n , MH m -KOH, M: Li, Na, Mg) were prepared by ball milling method. We expected reaction formula of these six systems with assumption, that is, oxides would form after dehydrogenation. The hydrogen desorption properties of these systems were evaluated by TG-DTA and MS. From the results of XRD before and after dehydrogenation, we obtained actual reaction formulas, which were different from expected formulas.Among six systems, it was confirmed that only KH-LiOH system dehydrogenated in endothermic. This means that KH-LiOH system can reversibly ab/desorb hydrogen in principle. However, it is calculated that extremely high pressure of GPa order is required for rehydrogenation of KH-LiOH system.