Tongxingsi rock is a famous alkaline intrusion in North Huaiyang tectonic belt. Tongxingsi alkaline intrusion has the features of medium contents of SiO2 and Al2O3, alkali rich, aluminum -to-be, and low Mg#.. It enriches large ion lithophile elements such as Rb、Ba、Sr, and depletes high field strength elements such as Ta、Ti. The ratio of LaN/YbN and LREE/HREE are all larger. It has weaker negative anomaly of δCe. It belongs to LREE rich type for its REE distribution patterns indicate the LREE is steep while the HREE is relatively flat. Tongxingsi monzodiorite and hornblende syenite were dated to be 126.1±1.1 Ma and 124.4±1.3 Ma, which indicates it belongs to the second magma activity products of Tongxingsi complex intrusion in the early Cretaceous. The major and trace element geochemical analyses indicate the magma came from partial melting of the mantle and contaminated by continent crust. Based on the integrated results of previous studies about regional geological background and geochemical tectonic environment discrimination of this study, the paper considers Tongxingsi alkaline intrusion formed at the post-collsional extension setting.