The invention relates to celeste blue glaze and a preparation method thereof. The celeste blue glaze is prepared from, by mass, 48-51 parts of melilite, 14-16 parts of drug, 14-16 parts of calcite, 11-13 parts of quartz, 5-8 parts of talc and 0.4-0.6 part of bone ash; the preparation method for the celeste blue glaze comprises the following steps that S1, the raw materials are weighed according tothe matching ratio, water is added into a ball grinder for grinding the raw materials, after grinding, the ground raw materials are sieved by a sieve, and glaze paste is obtained; S2, blank bodies are manually soaked in the glaze paste; S3, the blank bodies are placed in a kiln for firing and heated for 3 h at the 300 DEG C/h speed under an oxidizing atmosphere to 900 DEG C, after the temperatureis kept for 3 h, the heating speed is controlled to be 55 DEG C/h, the temperature reaches 1020 DEG C, after the temperature is kept for 2 h, the heating speed is controlled to be 110 DEG C/h, undera reducing atmosphere, the blank bodies are heated to 1240 DEG C, after the temperature is kept for 0.5 h, the blank bodies are cooled naturally, and the celeste blue glaze is obtained; by adopting the formula and the preparation method, the fired jun porcelain glaze color is bright and smooth, and the glaze is bright, high in artistic value, wear-resisting, solid and durable; the optical propertyof the melilite is sage green, yellow and brownness, and a thin melilite piece is colorless.