Abstract: A method for manufacturing a powder for sendust core is disclosed which is used in power supplies, converters and invertors, and in which the sendust powder is manufactured by applying the atomizing process, and the powder is coated with a special ceramic mixture insulator, so that the core loss would be small after forming a product. The method for manufacturing the powder for a sendust core includes the steps of: preparing a sendust alloy melt composed of (in wt %) 4-13% of Si, 4-7% of Al, and balance of Fe under an inert atmosphere; spouting water with a pressure of 1500-3500 psi to a flow of said sendust alloy melt through four or more nozzles having a diameter of 10-20 mm, so as to form a relatively regular polyhedral powder; adding 0.1-1.0 wt % of kaoline to the powder, and heat-treating it at a temperature of 700.degree.-850.degree. C. for 30 minutes or more under a reducing atmosphere; and carrying out a wet coating on the heat-treated powder by using 0.