Mafic and ultramafic rocks of later paleozoic period in Emei igneous province consist of two rock series： picriteperidotite and basalt suites，whose bulk and trace element characteristics are quite different，which can be further proved by comparing the abundance relationship between Ni and Cr、MgO、Al2O3 of the two rock series. According to the elemental abundance relationship，the paper estimates the Mg# (MgO/MgO+FeO)、bulk element、Cr and Ni contents of the mantle and the different parts of mantle plume in the Emei igneous province， makes the conclusion that the basalt （composition of which are close to that of primary magma）、 picrite and peridotite are products of different partial melting degrees of the mantle，the degrees of which are 7%～15 %，25%～40% and >50% ，respectively.