Abstract: In this stuty, a new type of modifier which adopted in Cr15Mo3 of abrasion white cast iron has been got. Molten iron has got cleannig after modification, the non-metall impurity, N₂、H₂ & other gas had also reduced. Ti which is contained in modifier formed TiN with N₂ in molten iron, and TiN is the core of solidification of austinate & thined the austinate dentrite, RE in modifier is a surface active active element, adsorbed on the intersurface of carbide, slowed down it's grouth & made it more tinier. The castings of mud pump poured using molten iron which had been modified, got 8000 hours useful life & still used by now. But for non-modification one is only 4000 hours the highest. Adopt this new technique,Beijing Industrial Pump Factory got 1.09 million yuan increaced benefit per year,by the widely reducing of rated of rejects.