Chinese food is delicious. There are many kinds of cuisine. But the stir-fry, fry and deep-fry produce a large amount of steam and smoke which cause indoor air pollution seriously. So it must be controlled. The paper gets some flow distribution regularity of steam and smoke current in Chinese cooking by testing in laboratory and advances a new method to prevent the diffusion of smoking current-kitchen hood with forced air screen. By comparing with other removers, the equipment can save heat (cold) load and improve indoor air condition greatly. The paper also analyses blow and draw current of the equipment by fluid mechanics theories.