Abstract: The Jinchuan super-large Cu-Ni sulfide deposit is a world famous deposit,it has the characteristic that small intrusion formed large deposir.Based on the geological and geochemical information,the authors discuss the differentiation relation of this deposit:①The,inchuan Cu-Ni sulfide deposit was formed in the Mesoproteroaoic Changchengian Loagshoushan-Qilianshan rift zone.②The metallogenic magma was picritic magma.it belong to the tholeiite series,and it was the product of partial melting of mantle rock.③The metallogenic magma derived from sulfur rich mantle,and the magma was rich in minerals at the beginning.④The metallogenic substance were further concentrated during the magma evolution process.and the magma occurred many pulsatile intrusion after deep differentiation in the crust trantsitton magma chamber.There was four times invasion to formed the existent ore-bearing rock bodies.The first and second invasion carried sulfide droplet and peridot crystal in the silicate magma,and formed the low grad ore bodies in local place.The third invasion carried a large quantity of olivine crystals and sulfide droplets,and formed rich ore bodies.The fourth invasion carried more magma sulfide,and all the magma formed special rich ore bodies.