Abstract: From the perspective of the epistemology in broad sense, the cognition directing to the object itself, the evaluation which take the meaning of the object to the human being as its contents, and the normativity with the guidance of the idea activity and practice as its purport constitute the relevant aspects of human knowing, and the concrete form of human knowing is correspondingly embodied in the unity of cognition, evaluation and normativity. Cognition is inseparable from perceptual materials and conceptual forms which have their own sources of reality. In the context of the interaction between the known and the knowing, the cognitive process involves both ontological and metaphysical premises. On the one hand, the cognition involved in the evaluation process is based on the premise of grasping the properties of things; on the other hand, it is based on the conditions of identifying with reasonable value principles. From the perspective of epistemology in broad sense, the interrelation of cognition, evaluation and normativity provides a premise for the connection between the explanation of the world and the changing of the world.