Objectives: Mesozoic volcanic rocks are widespread in eastern China. In Shimenzhai, Qinhuangdao, northern Hebei province, there occur a suite of Mesozoic volcanic rocks of the Lanqi Formation and the Sunjialiang Formation, unconformitly overlying on the Jurassic conglomerate of the Beipiao Formation. The Lanqi Formation consists of tephrites, trachyandesites and tephrites, and the Sunjialiang Formation mainly consists of dacites and rhyolites. The petrogenesis and age of volcanic rocks of the Lanqi Formation and the Sunjialiang Formation in Shimenzhai, Qinhuangdao, Hebei province is important for discussing mechanism and timing of thinning of North China Craton in Mesozoic. Methods: Whole rock geochemistry analysis and zircon U- Pb age dating are carried out on selective volcanic rocks samples of the Lanqi Formation and the Sunjialiang Formation. Results: The volcanic rocks of the Lanqi Formation are mafic alkaline, with high K, Na and Al contents, some of samples also have high Mg and Fe contents. Trachytes and trachyandesites are enriched in LILE and LREE, depleted in HFSE and HREE. Tephrites are slightly depleted in HFSE, with significant fractionation between LREE and HREE. Basalts have no HFSE anomaly, LREE enrichment and HREE depletion. The volcanic rocks of the Sunjialiang Formation have high K, Na, Al, and low Mg and Fe contents. They have LREE enriched patterns, with significant negative Eu anomalies. The Lanqi Formation is mainly shoshonite series, and the Sunjialiang Formation is high K calc alkaline series. Conclusions: The geochemical characteristics of trachyte and basaltic trachy- andesite of the Lanqi Formation are similar to those of island arc, which may be related to the subduction and dehydration metasomatism of the upper crust. The geochemical characteristics of tephrite are similar to those of HIMU type OIB, and the source region may be enriched asthenospheric mantle by metasomatism of the subducted oceanic crust. The geochemical characteristics of basalt are similar to those of N- MORB, and the source area may be depleted asthenospheric mantle. The rhyolites of the Sunjialiang Formation may be partial melting of lower crust by underplating of mantle source magma by the Early Cretaceous extension of North China Craton or the partial melting of subducted oceanic crustal rocks by subduction of the palaeo- Pacific plate. LA- ICP- MS U- Pb dating on zircons from a rhyolite of the Sunjialiang Formation, yield a concordant age of 118.0±1.1Ma. This age indicate that the Sunjialiang Formation is chronologically comparable with Yixian Formation in western Liaoning province.