The invention relates to a preparation method of dielectric ceramic K6Nb10.8O30 powder and a sintering body of the dielectric ceramic K6Nb10.8O30 powder. The preparation method of the sintering body of the dielectric ceramic K6Nb10.8O30 powder comprises the following steps: mixing Nb2O5 with KOH, calcining and then dissolving mixture in water, carrying out titration with nitric acid until pH value is 2-3, collecting precipitate and dissolving the precipitate in oxalic acid; carrying out titration with ammonia water until the pH value is 10-11, so that white precipitate is obtained; dissolving the white precipitate in citric acid, so that a solution I is obtained; dissolving K2CO3 in water, so that a solution II is formed; mixing the solution I with the solution II, heating, so that sol is obtained, and drying at the temperature of 80-130 DEG C; treating aluminium hydroxide dried gel for 2 hours at the temperature of 300-400 DEG C; then calcining at the temperature of 950-1000 DEG C; after extrusion moulding is carried out on the K6Nb10.8O30 powder, sintering is carried out at the temperature of 1100-1200 DEG C, so that a ceramic body is obtained. The invention has the advantages that a production method is simple in technology, energy consumption is low, the K6Nb10.8O30 powder is of a pure square tungsten bronze phase structure and uniform in morphology; the provided electronic ceramic has high density and excellent dielectric properties.