“National Japan-Resisting United Battlefront” was one of the most successful exercise of tactics in Chinese Communist Party’s (CCP) history of united battlefront, and also the one that changed CCP’s history forever. It had crucial influences on CCP's growth in strength and the establishment of the regime latter. The text simplifies matters and makes an analytic differential demonstration concerning several controversial questions of research scholars ： When was National Japan-Resisting United Battlefront put forth? Was it solely put forth by CCP or the authorized decision of its leading organization “Comintern”? What was the attitude of National Japan-Resisting United Battlefront to “Chiang Kai-shek (Chiang)”? Whether the considerations of CCP and Comintern were identical or not from original “opposing Chiang” to “alliance with Chiang” and “supporting Chiang” afterwards? What factor made the former policy convert? What were the content and the nature of National Japan-Resisting United Battlefront? Distinguishing the above-mentioned questions will be beneficial for us to understand CCP’s position, character, and status in the history of resisting against Japan.