A largebodied tyrannosauroid was firstly discovered at Dachengzi Town, Harqin Left Mongol Autonomous County， western Liaoning Province. The geological surveys and section measurements were carried out around and at fossil site. According to the comparison of the measured sections to the typical section in the Dachengzi Basin, it is concluded that the tyrannosauroidbearing strata are the First Member of the Lower Cretaceous Jiufotang Formation. Moreover, the analyses of sedimentary and taphonomic environments reveal that the large tyrannosauroid was preserved in situ and buried in diara deposits.