The Fanshan potassic alkaline complex was formed by three periods of intrusive rocks,which were all penetrated by vein rocks. The first period intrusive rocks are layered ultramafic rocks that have rhythmic structure. Gigantic apatite-magnetite deposits occur in layered rocks.he main types of first period intrusive rocks are pyroxenite, biotite pyroxenite, pegmatoid orthoclase-biotite pyroxenite, magnetite apatite rock, apatite rock and interstitial orthoclase pyroxenite; the second period intrusive rocks might be divided into three rock types, viz., coarse- grained orthocalse pyroxenite, coarse-grained pyroxene syenite, and coarse-grained schorlomite-orthoclase pyroxenite; the main types of the third period rocks include trachytoid pyroxene syenite, fine-grained orthoclase pyroxenite, fine-grained pyroxene syenite and porphyroid pyroxene syenite. The three kinds of vein rocks are syenite, hornblende syensite and carbonatite.Au abundance (6.1×10-9) of the Fanshan complex is 1.74 times that of the crust (3.510-9). The determination of rocks of different intrusive periods suggests that the average Au content of the first, second, third period rocks and vein rock syenite are 8.8×10-9, 5.1× 10-9, 7.4×10-9and 4.2×10-9, respectively. In addition, Au content of various rocks of the irst period was determined: pyroxenite 9.31×10-9, biotite pyroxenite 7.78×10-9, pegmatoid orthoclase-biotite pyroxenite 7.40×10-9, interstitial orthoclase pyroxenite 8.00×10-9,magnetite apatite rock 13.78×10-9, apatite rock and biotite-apatite rock 11.80×10-9, and biotite rock 18.63×10_9. These data suggest that Au content shows vertical rhythmic variation in the profile of the layered rocks, and decreases from west to east. These phenomena imply that Au tended to concentrate in the melt with high content of Fe, Mg, Ca and P during the primary magmatic differentiation and then became richer in the fluid due to magmatic fractional crystallization.