Cardiovascular diseases (CVDs) and malignant tumors are the main causes of death worldwide. The etiology study of CVDs and malignant tumors has found a series of widely recognized risk factors. Medical practice and medical theory usually focus on one of the diseases, but more and more evidence reveals that malignant tumors usually involve the cardiovascular system, thus leading to thromboembolism, heart failure, etc. Anti-cancer treatment proves to induce CVDs, while CVDs seem to increase the risk of malignant tumors. This situation requires researchers to conduct further combined crossover study on both CVDs and malignant tumors. In this review, we discuss the potential common risk factors of cardiovascular diseases and malignant tumors, the pathological and physical mechanism of the two kinds of diseases, the cardiac toxicity induced by tumor therapy and the impact of cardiovascular drugs on cancer from the perspective of cardio-oncology, and in the endput forward the prospect of prevention and treatment.