As far as the genesis of Sibao granodiorites in North Guangxi is concerned, the granodiorites are believed as differentiated granites derived from the mantle by Mo Zhusun(1980)and Wang Dezi (1982)，and are regarded as I type gran- ites which were made up of a pair of granite belts with, the S type biotite granite at the southern margin of Yangtze massif by Zhao Zijie (1985) and Peng Daliang (1986).This paper describes the results of petrological，mieralo- gical.geochemical, trace element and isotope study of the granodiorites, Com- bining above the results with the regional geological evolution and the study on radiometric ages of the granodiorites,authors suggest a new idea, the gra- nodiorites are a mixed source type granite mai}My derived from the crust and less from the mantle in stead of differentiated granite derived from the ma- ntle or typical I type granite.