As the most common grain boundary strengthening elements in Ni-based superalloy, C and B are inclined to form carbides and borides with other elements, thus influence the mechanical performance of superalloy. In this paper, the evolution of the carbides and borides in a Ni-based superalloy during creep is studied. Through analyzing the creep mechanism at different conditions, and comparing the morphology, distribution and crystal structure of carbides and borides before and after creep tests, the influences of creep condition on the precipitation and evolution of carbides and borides are investigated, and the effects of carbides and borides on the creep properties of Ni-based superalloy are revealed.