The Diary of Chen Cheng was discovered by the present author when he was doing research in Taiwan recently. It is one of the most important sources on the history of Taiwan. Naturally, it is an important source to study the relationship between Chiang Kai-shek and Chen Cheng. Prior to 1965, they were the two foremost figures in Taiwan's political life after the Nationalist Regime retreated to the island. In the past decades, however, scholars overemphasized the two men's intimate co-operations, stressed Chiang's trust on Chen, highlighted Chiang's elevation of Chen to the highest political status, and underlined Chen's unconditional loyalty to Chiang. Without a doubt, both men had their own deep-seated long-term personal tie. Yet, The Diary of Chen Cheng reveals the two men's conflicts and their confrontation in Taiwan.  In the early 1950s and soon after the relocation of the Nationalist regime to Taiwan, Chen Cheng indeed strongly supported Chiang to be the supreme Nationalist leader|nevertheless, he, at the same time, questioned Chiang's ability and his working style. Between 1958 and 1961, the two men clashed over a number of issues in regard to Chen Cheng's reshuffling of ″the cabinet,″ and other issues such as personnel arrangements, the ″third presidential election,″ and the invading expedition into the mainland. Sometimes, Chen even defied Chiang in front of him. This obviously presents a more complicated historical scenario which differs from what we previously received from other scholastic conclusions. This article makes full use of the historical facts from the diary and analyzes his clash with Chiang over some issues.  There are three new features here that deserve special attention: (1) New primary sources are offered. This is the first time a scholar uses The Diary of Chen Cheng to do the relevant research on the two men's tie. (2) New perspectives are presented. Differing from the previous views that emphasized the two men's close relationship, this article points out that they had clashed over many issues during their Taiwan years. Occasionally, their conflicts reached an unbearable apex for both of them. (3) New approaches are adopted. In analyzing the conflicts, the author combines The Diary of Chiang Kai-shek and this diary for the purpose of reaching a more objective yet new conclusion. No doubt, this topic is significant, because it helps future scholars do research on Taiwan's political developments and even on Chiang Kai-shek as the Nationalist leader during an important decade between 1950 and 1960.