The invention discloses a cobalt-containing stratified potassium titanate laminar particle and a hydrothermal preparation method thereof and belongs to the field of material preparation. TiO2 and Co(NO3)2.6H2O are added into a KOH water solution, stirring is performed to uniformly mix the raw materials for a hydrothermal reaction, and after finish of the reaction, filtering, washing and drying areperformed to obtain the cobalt-containing stratified potassium titanate laminar particle. The laminar particle has the composition expression formula of K0.8Co0.4Ti1.6O4,and is 1-2 [mu]m in length and 100-200 nm in thickness. Compared with a traditional solid-phase method and a traditional molten-salt growth method, the hydrothermal preparation method has the advantages that the prepared laminarK0.8Co0.4Ti1.6O4 laminar particle is small in grain size, high in purity and controllable in shape and microstructure, and the hydrothermal preparation method is simple in preparation process, low inenergy consumption, high in repeatability and favorable for industrial production.