Abstract: In view of the interdisciplinary nature of Foucault’s writings,this paper argues that Foucault’s thought is not only trans-limits,but also transgressive,transgressing the intrinsic limits of the disciplines and engaging in a different kind of thinking and inquiry,which knocks down,shakes up,and even destroys the traditional doctrines of thought.Foucault not only wants to break through the limits of Cartesian rationalism,but also to eradicate Kantian anthropological subjectivism and Husserl’s philosophy of transcendental subject,and not only to cut off the chain of linear causality of traditional historicism,but also to overstep the ideological minefield of the essentialist view of power.Foucault esteemed the critical spirit of Marx,Nietzsche,and Freud,and criticized the traditional philosophical view of Reason,of History,of Subject,and of Power.Although Foucault’s writings have different focuses at different times,they all focus on interpreting his lifelong conviction that “thought is the discourse about limits and their transgression”.Foucault played the role of a transgressor in the philosophical theater,holding high the flag of difference,bravely transgressing the limits of modern philosophy of Identity,of Representation and of the Absolute, creating a new field of research of thought,and presenting a new philosophical conception of philosophy as a diagnosis of the times.Every transgression is a breakthrough in conception and an advancement of thought.Of course,Foucault’s transgressions have their theoretical limits,and his critical characterization of Sartre’s and Merleau-Ponty’s thought is not entirely accurate.In short,in a sense,it can be said that whereas Descartes intuited “I exist thinking”,and Marx advocated “I exist laboring”,Foucault practiced “I exist transgressing”.