Present study conducted a Natural Language Processing procedure to test the content validity of the hot research issues identified by titles, abstracts, keywords and full text of academic papers. The findings include: Firstly, the hot research issues identified by keywords facing a high validity risks. Secondly, the content validity of hot research issues identified by titles are highest compared to other analysis unit from a comprehensive perspective. Thirdly, the hot research issues identified by various units are unstable from perspective of solo-index.