The invention belongs to the technical field of coal catalytic gasification catalysts, and provides a coal catalytic gasification catalyst for fluidized beds, and a preparation method thereof. The coal catalytic gasification catalyst is the mixture of potassium carbonate and one or a plurality of organic potassium salts, and is prepared by using an excess impregnation method, wherein the active component and the carbon-based material are combined through strong acting force, and the active component is highly dispersed on the carbon-based material. Compared to the single potassium carbonate catalyst, the catalyst precursor potassium salt mixture of the present invention has the low eutectic point, is easily converted into the liquid state from the solid state in a gasification reaction, can permeate into the more carbon-based material gaps, and is supplemented with the synergistic effect of the anions in the mixture potassium salt so as to improve the coal gasification efficiency, improve the methane content in the product gas, reduce the proportion of the inactive potassium aluminum silicate generated from the reaction between the potassium and the silicon, the aluminum and other substances in the carbon-based material during the gasification reaction, and improve the effective utilization rate of potassium.