Master Xuyun is a great Chan Master who has a great influence on modern Chinese Buddhism. Kanhua Chan (看話禪) has been known as the important doctrine of Chan school from Song Dynasty since Dahui Zonggao advocatedthis method. Dahui mentioned that making good use of the word “Wu” (nothing, 無) in Huatou (話頭) meditation could release us from the cycle of rebirth, so he regarded the word “Wu” as the key to Huatou. Master Xuyun also advocated the practice of Kanhua Chan but he proposed Huatou a new definition as a state of “one thought not arising,” (一念未生) i.e. when a thought has come up, it can’t be counted as Huatou anymore. This viewpoint is quite different from that of Dahui. In this essay, I will try to analyze Xuyun’s teachings of Kanhua Chan in two stages. The first is about the arising of doubt sensation; the second KanHuatou itself. Through the approach of Master Xuyun, we can have a clear understanding about how his Huatou thought characterizes his teaching on Kanhua Chan. A comparison between Xuyun and Dahui discussed reveals that they have emphasized on their teachings differently. In my opinion, Master Xuyun’s concept of Huatou has been immensely influenced by Huineng’s idea of “Mindlessness.” (free from false thought, 無念) Basing on the concept of “Mindlessness,” Xuyun gave Huatou a specific definition and clear explanation in order to guide students to take the true meaning of Huatou during their “Chan practicing.” In his essay Chenbing mentions that a lot of teachings about Kanhua Chan has been practiced, but few of them it’s true meaning has been inquired deeply, except for Master Xuyun who has clear explanation and teachings of Huatou. Chenbing also mentions that the content of Xuyun’s theory about “one thought not arising” is equal to “nature mind,” which has been initially raised by Tiantai school’s Master Huisi. In my opinion, Xuyun was influenced more by Huineng’s idea of “Mindlessness” than by Master Huisi. Thus, this article will not only focus on Master Xuyun’s teachings about Huatou but will explore how Master Xuyun is inspired by Huineng’s idea of “Mindlessness” and proposes his theory of “one thought not arising.” This paper will also discuss some Xuyun’s interpretations of The Śūraṅgama Sūtra (楞嚴經) and The Awakening of Mahāyāna Faith (大乘起信論) , and go further to investigate and analyze how his “one thought not arising” theory bridges the teachings and practices of Kanhua Chan taught by Xuyun Master. In addition, I’ll also explicate the common perspective between “one thought not arising” and Mozhao Chan.