在渤海史研究中，由于众所周知的原因，渤海族属问题成了争论的焦点。而产生分歧的症结又与对《旧唐书·渤海传》中“别种”一词的理解有很大关系。史书中“别种”一词，多用于记述民族关系。汉魏至宋代史书如《北史》、《周书人好书》、《后汉书》和新旧《唐书》中皆有使用。 In the history of the Bohai Sea, due to its well-known reasons, the Bohai ethnic issue has become the focus of controversy. And the crux of the disagreement has a great relation with the understanding of the word “other species” in “The Old Tang Dynasty · Bohai Sea Biography”. The word “other species” in history books is mostly used to describe ethnic relations. The Han and Wei Dynasties to the Song Dynasty history books such as “Northern History”, “Zhou book good man”, “Han” and old and new “Tang” are used.