Abstract: Three cross sections of paleovalley depositional sequences were established based on bore data and documents of Nanjing No.3 Bridge,the Yangtze River Bridge and Nanjing No.4 Bridge. Through ¹⁴C dating to samples from 4 drilling cores near the Nanjing No.4 Bridge which is proposed to construct, it is discovered that the paleovalley at the -60~-90 m depth near Nanjing existed within the period of last glacial maximum. It is also indicated that the deep incised-valley channel was narrow and the river flowed swiftly.Drilling shows that the valley channel ran deep locally near the Nanjing Yangtze River Bridge,like a "V" shape.