The swirl air curtain exhaust hood (SACEH) is a new type of exhaust hood used in local ventilation. Based on analysis of theory, the flow field and the deleterious substances distribution of SACEH were simulated by CFD software Fluent, which was compared with the ordinary exhaust hood (OEH). The results show SACEH can effectively control the deleterious substances and greatly improve the suction. Therefore, it realizes long-distance trapping and low velocity emission of deleterious substances. At last, we verified the conclusion from numerical simulation by model experiment.