Jaspers devoted a special chapter to Kant in his book Great Philosophers. From this, we can see that Jaspers firmly defended the fundamental spirit of Kant's "transcendental humanism" and paid sincere respect to the formal power endowed by his "critical rationality." Jaspers was a philosopher focused on "things in itself," and when he absorbed Kant on the basis of his aspired "existential humanism," a unique atmosphere came out, brought about by the slight deviation in the focus and approach of his philosophical thinking. To be more specific, it was mainly manifested in two aspects:first, the "existential humanism" aspired by Jaspers is also a kind of "humanism", but its focus falls on the "existence" with historical consciousness after all; Secondly, the "philosophical logic" to which Jaspers devoted himself is of course also a "logic" that appeals to the formal power of "rationality." However, the pure formal rationality is examined from the perspective of "existence". Jaspers believed that rationality with the power to awaken people still needs to be continuously supplemented and realized in history and in the world by individual existence through free choice.