The invention discloses a production method of a UU80 magnetic core. The production method includes the steps of firstly, producing powder, wherein iron oxide red silicon content in the raw material is smaller than 100ppm, silicon dioxide and vanadium pentoxide are not added, grinding time is 90 minutes, gel adding ratio is 0.7wt%/batch, magnetization degree is smaller than 3m<2>/kg, and Cl<-> issmaller than 350ppm; secondly, forming, to be more specific, coating each of the upper die and the lower die of a die with a CrAlTiN layer to increase the smoothness of the die and reduce film adhesion after forming; thirdly, sintering with a specific process curve to guarantee that a sintered product is free of cracks and crystallization is reduced, wherein highest sintering temperature 1320 DEGC, and gel discharge time is 450 minutes; fourthly, using a disc grinder to directly grind the product to standard size so as to guarantee the smoothness of the ground product and reduce unfilled corners and chipping. The method has the advantages that each procedure from powder production to grinding is improved, badness such as product crystallization and film adhesion after sintering is reduced, and the quality requirements of clients can be satisfied.