Since e-cigarettes enter the markets, its awareness and use have increased significantly. There are multiple harmful substances in e-cigarette liquid. Using e-cigarette may cause nicotine addiction, affect various human body systems, and even aggravate the harm of traditional tobacco. At present, the e-cigarette market is lack of legal constraints and regulatory measures. For the individuals who attempt to use or regularly use e-cigarettes, especially teenagers, it is necessary to provide proper guidance and education. Based on the research articles at home and abroad in recent ten years, the chemical composition of e-cigarette liquid and aerosol, individual health risk of e-cigarette use, and the risk of e-cigarette equipment were summarized, aiming to provide reference for the safety of using e-cigarettes. Through the introduction of the composition of e-cigarette liquid and aerosol, we should guide the correct cognition of the hazards of e-cigarettes. Based on the individual health risks generated by using e-cigarette, we should prepare the propaganda materials on the hazards of e-cigarette. Based on the risk of e-cigarette equipment, we should warn people that there are hidden dangers in the use of e-cigarette. It calls for legislations and regulations targeting e-cigarette as soon as possible, and more intervention measures to deal with the impact of e-cigarette on human health.