The invention provides a ceramic mould casting process for a magnesium alloy. The flow of the ceramic mould casting process for the magnesium alloy is as follows: carrying out female die treatment, brushing silicon rubber, vacuumizing, filling with gypsum, drawing a silicon rubber/gypsum die, preparing a hydrolysate, preparing a ceramic slurry, grouting, drawing the die, carrying out spray combustion, roasting, producing a sand mould, smelting the alloy, pouring, unboxing, inspecting, and setting die drawing time for spraying a refractory material according to the sizes of workpieces, wherein the die drawing time of the small workpieces is about 5 minutes, and the die drawing time of the large workpieces is about 20 minutes; the roasting temperature is 850 DEG C, the temperature rise speed is 3 DEG C/min, the insulation time is 1 hour, and organic matters are eliminated to prevent the reaction between the sand mould and the magnesium alloy. The ceramic mould casting process for the magnesium alloy enables the casting effect to be good, and the cast product is good in quality.