Abstract: This article is based on reducing the power loss of metal magnetic powder core, and uses iron, silicon, silicon aluminum, and iron nickel magnetic powder core as the research object. From the composition of alloy powder, the impact of the magnetic core loss of the real vacuum and powder particle size of the powder. The effect of Si component content on the loss of iron silicon magnetic powder core, the effect of alloy powder melting real vacuum on the iron silicon aluminum magnetic core, and the effects of different particle size on the iron nickel magnetic powder core. The results show that in the ingredients of iron and silicon magnetic powder core, the Si content is increasing at 4.5wt.%~ 6.5wt.%. Under the same inductance, the loss gradually decreased, the minimum loss at 6.5wt.%Reached 374 mW·cm- 3 (50 K/100 mT).During the smelting of FeSiAl alloy powder, as the smelting vacuum degree decreases, the oxygen content of the alloy powder gradually decreases, and the magnetic powder core loss gradually decreases. At a vacuum degree of 5 Pa, the loss is as low as 85 mW·cm- 3 (50 K/100 mT).In terms of the particle size of the iron-nickel magnetic powder core, the finer the powder, the higher the oxygen content and the lower the loss. The loss is lowest at -400 mesh, which is only 120 mW·cm- 3 (50 K/100 mT).