Tree-ring width chronologies of Sabina Tibetica were constructed based on tree-rings of 1061-year sampled in Tianjun county of Lake Qinghai Basin. The response function analysis showed that the chronologies were sensitive to the annual precipitation so that the paper reconstructed annual precipitation series. The cross-validation method was used to check in the stability of the calibration equation, and the result indicated that the equation was stable and the variation of reconstructed annual precipitation was dependable and representative. There were six years showing precipitation below normal stage, which were periods of 1001 to 1060, 1131 to 1320, 1411 to 1510, 1691 to 1740, 1811 to 1850 and 1911 to 1940. There were seven years that showed precipitation above normal stage, which were period of 961 to 1000, 1061 to 1110, 1321 to 1410, 1511 to 1650, 1741 to 1790, 1881 to 1910 and 1941 to 2000. The occurrence of abrupt precipitation was once a time every 53 years．Reconstructed precipitation series showed an unstable period from the 13th to 14th centuries, but stable periods in the 12th, 17th and 20th centuries.