The invention relates to a preparation method of silicon carbide nanometer particles capable of absorbing organic dyes with high efficiency, and belongs to the field of absorbent preparation and waterenvironment purification. According to the preparation method, sucrose and the like are taken as carbon sources, a nitrate is taken as a catalyst, sodium silicate is taken as a silicon source, and sol-gel method is adopted to prepare a carbon silicon binary xerogel; the carbon silicon binary xerogel is subjected to carbon heat reduction reaction at 1000 to 1400 DEG C under the protection of argonor nitrogen atmosphere, and cooling to room temperature is carried out so as to obtain a primary product; the primary product is subjected to calcining at 500 to 800 DEG C in the air to remove unreacted carbon, and is immersed in an acid for 24 to 72h so as to remove other impurities; and washing and drying are carried out so as to obtain the silicon carbide nanometer particles. The silicon carbide nanometer particles are added into a simulated dye waste water solution as absorbents. Operation of the preparation method is convenient; equipment requirement is simple; economical value is high;the specific surface area of the prepared silicon carbide nanometer particles is relatively large; the silicon carbide nanometer particles can be recycled, is high in efficiency in treatment of dye waste water, and possess excellent absorption performance.