With the development of society, tumor has developed into a common and frequent disease that seriously endangers people’s lives, and is known as one of the three major deaths in the world together with cardiovascular and cerebrovascular diseases. Chemotherapy is one of the commonly used therapeutic methods for tumor treatment at present. The side effects of chemotherapeutic drugs have also been paid more and more attention to. In addition to the obvious toxic side effects of chemotherapeutic drugs on bone marrow, gastrointestinal tract, hair and reproductive organs which are usually considered to be the most common side effects of chemotherapeutic drugs, the clinical studies in recent years have found that: many chemotherapeutic drugs have certain toxicity to the heart, and with the prolongation of the survival period of the tumor patients after chemotherapy, the cardiotoxic reactions caused by them will also become very common. Although the cardiotoxic reactions seen clinically are much lower than those of bone marrow and gastrointestinal tract, once they occur, they can often cause irreversible damage to the myocardium, especially for those patients with pre-existing organic heart disease, the risk is even greater. Chemotherapeutic drug-induced cardiotoxicity varies in clinical manifestations: mildly asymptomatic but only electrocardiographic changes, severe myocardial necrosis, lethal congestive heart failure. The degree of manifestation is greatly related to the type of drug used, the dose, the method of administration and individual differences. Currently commonly used drugs that can cause cardiotoxic reaction of cyclophosphamide, Zoerythromycin, adriamycin and epothilone, especially Zoerythromycin and adriamycin, the incidence of cardiotoxicity is higher. In addition, other chemotherapeutic drugs caused cardiotoxic reaction cases have been reported at home and abroad. For example, Maliran can cause endomyocardial fibrosis; 5-fluorouracil causes cardiac ischemia and myocardial infarction; mitomycin causes myocardial injury, and cytarabine causes pericarditis. Heart disease secondary to chemotherapeutic drugs can be sudden, but also in the unknowing gradually aggravated, its treatment with the same general heart disease treatment, but due to chemotherapy drugs caused by heart disease change stubborn, high mortality, so special attention should be paid to prevention. Since chemotherapy drugs can cause irreversible damage to the heart, how to prevent the cardiotoxicity of chemotherapy drugs during chemotherapy. Experts remind us that we may as well start from the following aspects: 1, clear indications for tumor chemotherapy, determined not to chemotherapy for those who are not suitable for chemotherapy, and not to chemotherapy as a kind of placebo therapy for patients with advanced malignant tumors; 2, for the obvious dose-dependent drugs, the cumulative amount of the drugs should be strictly limited, and at the same time, pay attention to the individual differences. 3. It should be used with caution for those with previous history of heart disease (e.g. hypertensive heart disease, aortic stenosis, coronary heart disease, etc.), while it should be contraindicated for those with recent activity. If heart disease is caused by tumor, such as cancerous pericardial effusion, and chemotherapy is needed, cardiac function must be monitored dynamically. If toxic drugs are used in combination due to the need of the condition, appropriate reduction of the dosage can be considered, and the drug should be stopped once there are obvious clinical symptoms and serious abnormality of electrocardiogram. 4, for elderly patients, with a history of mediastinal radiotherapy or several affirmative cardiotoxic antitumor drugs combined application, should be appropriately reduced. Because in these cases, the tolerance of cardiomyocytes is reduced. 5, the electrocardiogram before and after chemotherapy should be listed as routine, and those who have problems should be dynamically observed for a period of time, and if the QRS voltage is really reduced by 30% or more compared with that before the treatment, then the drug should be discontinued for any patient. 6, patients with previous heart disease, can be given sub-protection of myocardial drugs, such as ATP, enzyme Q10, compound Danshen tablets and Pansentin, etc. from 2 to 3 days before chemotherapy. It can be maintained for 3～7 days after stopping chemotherapy. 7, according to the characteristics of drug pharmacokinetics, improve the method of drug delivery, such as sub-dosing can reduce the toxicity of the drug, then give sub-dosing or the use of micropumps. For example, Adriamycin is usually given once for 3 weeks, and it has been reported in the literature that if the same dose is given once a week, it is safer and the efficacy remains unchanged.