A total of 1252 samples have been collected from Jurassic-Cretaceous sedimentary rocks near bird-bearing beds in the Chaoyang area, western Liaoning, for a magnetostratigraphic study with the aim of obtaining geo-magnetic polarity sequences recorded in Jurassic-Cretaceous formations. The results show that the geomagnet-ic polarity sequences of the Lanqi and Tuchengzi Formations are characterized by repeated normal and reversal polarity, while there is only one normal polarity in the Yixian Formation. Based on fossil records and isotope data, the magnetic polarity sequence recorded in the Tuchengzi Formation may correspond to the Tithonian, Kimmeridgian, Oxfordian and Callovian stages. According to the international Mesozoic magnetostratigraphic time scale, the age of the major part of the Tuchengzi Formation should be Late Jurassic and the age of the bot-tom of the Tuchengzi Formation Middle Jurassic. Based on the magnetostatigraphic study of the upper part of the Yixian Formation and new geochronologic data, the normal polarity recorded in the Yixain Formation corre-sponds to M16, which suggests that the age of bird-bearing bed should be Early Cretaceous and that the Jurassic - Cretaceous boundary in western Liaoning is most likely to be located between the Yixian and Tuchengzi For-mations.