The simple zircon U- Pb dating results of the early Cretaceous intrusives in the northern Xiaoshan Mountains contained complex geological information. The emplacement zircon U- Pb ages of the six granitic stocks were simple and clear, forming two periods of ~130 Ma and ~145 Ma. The complex single grain zircon age spectrum provided a new way to consider the regional tectonic background. The zircon U- Pb ages and trace element characteristics from the Baishiya stock were not only important for discussing their petrogenesis and deep processes, but also significant for establishing a precise chronological framework and an integrated genetic model of Yanshanian intrusives in the northern Xiaoshan Mountains.Methods: According to the detailed field obversations of the Bashiya stock in the Xiaoshan Mountain, western Henan Province, the zircon U- Pb dating and rare earth elements were analysed. Results:The dating sample named BSY03 from the Baishiya stock was porphyritic biotite monzogranite. There are 77 zircon spots in three tests were analysed, and 73 results of them were adjacent to n(207Pb)/ n(235U)—n(206Pb)/ n(238U) concordia, whose U- Pb ages were clustered in three groups of the ~132 Ma (15 spots), ~145 Ma (49 spots) and ~158 Ma (9 spots). The zircon age spectrum was formed. The weighted average age of the last group suggested the formation age of the Baishiya stock was 132.1±1.0 Ma in the early Cretaceous. The chondrite- normalized distribution of the rare earth elements (REEs) for the three zircon groups, the characteristics of light REEs depletion and heavy REEs enrichment were shown, and the positive anomaly of Ce and negative anomalies of Pr and Nd were obvious for the most zircon spots. The total REE contents of ~145 Ma and ~158 Ma groups were 694×10-6 ~ 2213×10-6 with average of 1309×10-6 and 950×10-6 ~ 1849×10-6 with average of 1360×10-6, respectively. The total REE contents of ~132 Ma group were from 429×10-6 to 2210×10-6, and mean value was 1495×10-6. The formation temperatures of the zircons generally ranged from 539℃ to 748℃, and the values of zircon formation temperature for the ~158 Ma group were higher than the other groups, which were 601 ~ 748℃ (average 662℃). The zircons formation temperatures of ~145 Ma and the ~132 Ma groups were 553 ~ 701℃ (average 633℃) and 539 ~ 717℃ (average 629℃), respectively. The Er, Yb, Lu, and Y contents of zircon spots increased with formation age from ~158 Ma, ~145 Ma to ~132 Ma. The Ce4+/Ce3+ values of ~132 Ma, ~145 Ma and ~158 Ma groups were 13.2 ~ 121 (average 69.7), 27.6 ~ 107 (average 70.3) and 3.53 ~ 81.4, showing the overall trend of increasing from ~158 Ma to ~145 Ma and decreasing from ~145 Ma to ~132 Ma. Conclusions: The Baishiya stock was the product of lithosphere delamination of the northern Xiaoshan Mountains in the early Cretaceous. The deep magma/fluid was discharged, making for mixture and reactivation of the upper magma/fluid reservoirs whose stage of incomplete crystallization mush. The magma/fluid that regained the ability of upwelling carried zircons (such as ~158 Ma and ~145 Ma zircons) to form the Baishiya stock in ~132 Ma.