Shuiquangou alkaline intrusive complex, which intruded into the Archean metamorphic rocks during Her-cynian orogeny, is the most important ore-bearing intrusive body in northwestern Hebei Province. The debate has been existed about the origin of the Shuiquangou complex for two decades. Based on the detailed Nd-iso-topic features study on the Shuiquangou complex and Archean metamorphic rocks. it shows that Shuiquangou complex is not the migmatization product of Archean metamorphic rocks. It is supposed that Shuiquangou alkaline intrusive complex was derived from inhomogeneous mixture of two kinds of magma, which were formed in under-melting from the mantle and in partly melting from the lower crust, respectively. Because of high speed of upward movement, these two kinds of magma have not enough time to mix and evolve sufficiently. Therefore , it causes that the isotope system of the magma evolved insufficiently and the intrusive complex lacks distinct petrographical facies. Moreover, the rock type, chemical composition and isotopic composition became more complicated when the intruding magma assimilated many wall rocks.