Clean Rooms, as specialized production environments, require air purification systems that are critical for maintaining internal cleanliness, ensuring product quality, and ensuring production efficiency. The design, operation, and maintenance of air purification systems should follow a set of general regulations and standards in order to assure the good performance of the air purification systems that, in turn, reject the airborne particulate matter, microorganisms, and others and confine themselves to the ample requirements of production processes in the sense of air cleanliness. This paper will outline the overall principles of Cleanroom Air Purification, and the paper will hope to serve as a valuable guide to the practitioners working in the related areas.