This study displays the new magnetostratigraphic results of a 330mthick sequence from Liang ZK05 borehole in Dalangtan, northwest Qaidam Basin. Four normal chron zones are recognized from magnetic polarity sequence of Liang ZK05 borehole, which are regarded as Brunhes, Jaramillo, Cobb Mountain, and Olduvai by comparing with the Geomagnetic Polarity Time Scale. For no Reunion subchron existing in the bottom of magnetic polarity sequence, the age of the 330mthick sequence is less than 2128 ka. The B/M boundary is located in 94 m. According to the average sedimentary rate based on magnetostratigraphic results, the age of top part of borehole is calculated to 111 ka and the bottom of borehole dates 2046 ka. Therefore, the molasse deposits of Liang ZK05 borehole terminated in 2 Ma, which indicates that the age of the uplift of Altyn Tagh Mountains was before 2 Ma. This uplift stage of Altyn Tagh Mountains is regarded as Qinghai-Tibet Movement Phase B, beginning at 2.6 Ma and terminating approximately at 2 Ma. Three magnetic excursion events have been extracted from the magnetic polarity sequence in the depth of 51～58 m, 207.5～212 m, and 249～252 m, which should be corresponding to Calabrian Ridge 2 (515～525 ka), Gardar (1465～1485 ka), and Gilsa (1567～1575 ka), respectively. On the basis of eight magnetic polarity sequences from Shen Zhenshu et al. (1993), plus two magnetic polarity sequences of Liang ZK05 and ZK02, we have established the new magnetostratigraphic age frame of Qaidam Basin by comparing with the latest Geomagnetic Polarity Time Scale.