Abstract: Yingzuihongshan pluton is located at the eastern part of Beishan metallogenic belt in western Inner Mongolia, which is mainly consists biotite monzonite, porphyritic biotite monzonite and potassic granite. Previous studies have different views on the formation age of the rock mass, that is, it was formed in Silurian or Devonian. In this paper, the LA-ICP-MS zircon U-Pb dating of porphyritic biotite monzogranite obtains an age data of (423.1±1.5) Ma, indicating that the formation age of monzogranite was formed in Middle Silurian. Yingzuihongshan pluton belongs to calc-alkaline-high potassium calc-alkaline, peraluminous rock series. In primitive mantle normalized spider diagram, the samples are enriched in large ions lithophile elements (Rb, Th, K), while they are depleted in high field strength elements (Ta, Nb, Zr, Ti), with relatively enriched Hf. These rocks are characterized by LREE enrichment and depleted HREE, with obvious Eu anomaly and "right-deviation" REE distribution. Based on the testing data and some previous research results, it's suggested that Yingzuihongshan granite was formed by partial melting of lower crust during the collision stage of continental blocks.