This article systematically researches the development of Zen's mindnature thinking. I believe that the mind-nature ontologies of the various Zen sects differ greatly, especially those between the Rulai-zen 如來禪, Zushi-zen 祖師禪 and Fendeng-zen 分燈禪. For instance, the mind/nature ontology of Rulai-zen is sincere, while that of Nanzong-zen 南宗禪 is self-minded. Those of Heze-zong 荷澤宗 and Hongzhou-zong 洪州宗 are nstantaneous-real-minded, with that of Shitou-zong 石頭宗 is tathata-minded.