In the process of 1:50000 geological survey for Hongling and two other sheets in Hongshishan area of the Beishan orogenic belt, the authors studied AR, NK/A, A/CNK and δEu values of Maanshanbei granite in the Beishan orogenic belt. Petrochemical and geochemical features all indicate that Maanshanbei granite is of the peraluminium to weakly peraluminium type in the transitional zone of calc-alkaline and K-high calc-alkaline series, with characteristics of the Sr-high granite. U-Pb dating of zircon from Maanshanbei granite_diorite yielded an average weighted 206Pb/238U age of (237.8±4.3) Ma. This isotope age of Maanshanbei granite-diorite-is of great significance in studying the tectonic evolution of Hongshishan area in the Beishan orogenic belt, Gansu Province.