The Taili gneiss complex is exposed in the western Liaoning Province and mainly composed of gneissic granites, biotite plagioclase gneisses and hornblende plagioclase gneisses. Zircon U-Pb dating of these rocks indicates that the gneiss complex was formed in the late Neoarchaean (2 510～2 559 Ma), with ages similar to those of the "Suizhong granite". This suggests that the Taili gneiss complex is an important part of Archean basement of the North China Craton. Field occurrences and rock textures suggest that the gneiss complex is a suite of migmatites derived from syn-deformational anatexis, of which the hornblende plagioclase gneiss represents the "palaeosome", which was generated by a very low degree of partial melting with a few felsic veins inside. The felsic veins show the general characteristics of "leucosome". The biotite plagioclase gneiss represents the "residuum" after the low degree of partial melting, whereas the gneissic granite is the "neosome" characterized by the highest degree of melting. These rocks display a good gradational relationship in mineral content and geochemistry. In combination with previous zircon Hf isotopic data, the authors have reached the conclusion that the Taili gneiss complex originated from the anatexis of Mesoarchean ancient crust 2.8～3.0 Ga in age and recorded an important regional magmatic event of crustal reworking.