The basic dike swarms are an important tracer for an extension event of the crust and are considered to be a key indicator of the reconstructed Rodinia. In this paper, the basic dike swarms in the Taojiayao of the Zhongtiao Mountain were investigated for their significance in the tectonic evolution of the North China Craton during the Precambrian period. Based on the geochronological and geochemical data it can be shown that the basic dike swarms are dominated by diabase with typical ophitic texture, and are mainly composed of plagioclase and clinopyroxene. Zircon LA- ICPMS U- Pb dates indicate that the crystallization age of the basic dike swarms is 1838±32 Ma, and that they belong to the tholeiite series and the K2O/Na2O is 0. 55~1. 89, low alkalinity (4. 41%~13. 29%), high FeOT (1. 08%~10. 15%) and REE (65. 2×10-6~481. 38×10-6) enriched in Rb, Th, U, Pbetc. but depleted in Nb, Ta, Zr, Hf and lower εNd(t) (-11. 04 to -2. 32). Based on the above data it is inferred that there is addition of crustal components to the magma. In the rocks, the consolidation index SI has a strong linear correlation with the MgO content but no correlation with the SiO2 content. It is proposed that MgO plays a leading role in the trend of obvious crystallization differentiation. The type of magmatic source of the dike swarm is enriched mantle (EM Ⅱ) which is mainly contaminated by crustal material in the source area of magma. The crustal material in the magma mainly comes from the addition of continental crust material during subduction, and is unrelated to the magmatic crystallization differentiation and the contamination with crust during the process of uplift. Therefore, these dikes belong to a series of Within Plate Basalt (WPB) and were formed in an extension setting after crustal collision.