Concealment of kinship is an important proposition in Confucian ethics, which reflects the contradiction between law and kinship. Previous studies on the concealment of kinship were either completely on the side of the law or on the side of family affection, without examining the limits of the concealment of kinship. By analyzing the thought of Gongyang School, this paper holds that in an ideal state, choosing family affection or law depends on whether you have political identity. If relatives violate the law, ordinary people can completely hide the crimes of relatives, while officials must punish their relatives according to the law, and only extremely limited sympathy can be allowed. If officials want to completely hide the crimes of their relatives, they must give up their political identity. The king should forgive his relatives for their rebellion against himself, other situations are the same as officials.