Abstract：This paper reports whole rock major and trace element from Keratophye in the Dayimalong area of the North Qilian organic belt. The SiO 2 of Keratophye is between 52.51%~55.46%, The Na2O content is high, ranging from 4.79% to 6.86%, The K2 O content is low, ranging from 0.16% to 0.93%. The Na2 O/K 2O ratio is 5.16~37.19, With low potassium pull spot series — medium potassium and calcium alkaline series of sodium rock characteristics. The rock consolidation index (SI) is between 15.03 and 23.59, and the Mg# value is between 39.9 and 52.14. On the rare earth element distribution map standardized by chondrite, the right- inclined type of light rare earth is slightly enriched, and there is almost no or slight Eu anomaly. The δEu is between 0.86 and 1.30 with an average of 0.98. On the trace elements of the original mantle standardized, the highfield strength elements such as Nb, Ta, Zr, Ti, and P are generally depleted, Y content ranging from 15.6×10-6 to 21.8×10-6, with an average of 18.77×10-6, both less than 20. The Th/Yb ratio is 0.59~1.38, with an average of 0.77, both of which are greater than 0.6. The Ce/Pb ratio is 4.31~7.79, the Nb/La ratio is 0.28~0.49, and the Zr/Nb ratio is 14.73~30.08, all indicating that it is an island arc volcanic rock. Combined with the regional geological background, we believe that the Keratophye is formed in the island arc environment, Its formation mechanism is: The mantle wedge material modified by the subduction plate fluid partially melts to form the parent magma. During the magma rise, The hot magma system undergoes separation and crystallization and is contaminated by the surrounding rock thermal brine. The hot brine brings Na and Si ions, and takes away Fe and Ca ions, thus forming a sodium- rich magma system.