The invention discloses a novel method for carrying out crop pest control and prevention by applying ozone water. The method comprises the following steps of: at the initial stage of crop diseases and pests, spraying the ozone water to crops, wherein the ozone water is used for ground pest control and prevention or is used for underground pest control and prevention. The method overcomes the defects of high cost, serious pollution and the like which are caused by the fact that conventionally, pesticides are applied to carry out pest control and prevention; and the method utilizes strong oxidizing property of the ozone water, can realize multiple purposes by applying the ozone water for once, is low in control and prevention cost, effectively saves manpower and material resources, is acted on the crops, has high utilization rate and high response speed, can kill various germs and viruses on fruit trees and vegetables and effectively solves the problems of pesticide residue and environment pollution which are caused by application of the pesticides.