Carborundum of the sample is determined by potassium fluosilicate titration.The Al2O3-SiC-C brick sample was melted with KOH and KNO3 in the nickel-rucible.Through the experiment,chose the best melt condition.The melting temperature was 700℃ and melting time was 15 min.The method can avoid on fire and explosion during the melt of the sample.At the same time.it diminished the damage of the nickel-rucible and it was easy to soak out.A self-made filtration device will replaced of ordinary filtration bottles,filtration part of the glass was replaced by plastic,only needed 1/4 filter paper ( filter paper diameter approximately is 40 mm),easy to wash and neutralization,greatly reduced the detection time.Measuring results conformed with the results of the national standard method.Relative standard deviation of determination result was less than 5%.