Preparation method of high-strength porcelain insulator

The invention discloses a preparation method of a high-strength porcelain insulator. The preparation method comprises the following steps: (1) preparing modified powder; (2) preparing a Si-Zr composite oxide; (3) preparing carbon-attached aluminum oxide powder; and (4) uniformly mixing the modified powder, Si-Zr composite oxide, carbon-attached aluminum oxide powder, magnesium oxide powder, potassium feldspar and clay to form a mixed material, carrying out wet ball milling on the mixed material, removing iron after ball milling, adjusting the water content to 23-25wt%, pressing to form a blank, drying the blank in an environment of 100-110 DEG C for more than 40 hours, then heating to 450-500 DEG C at a speed of 10 DEG C/min, calcining for 1-2 hours, and cooling to room temperature to obtain the high-strength ceramic material. And heating to 1250-1280 DEG C at the speed of 5 DEG C/min, sintering for 3-4 hours, cooling to 300 DEG C at the speed of 5 DEG C/min, and air-cooling to normal temperature to obtain th