Cardiovascular diseases are the first harm to people‘s health for a long period, in which a large portion are the chronic diseases of unknown etiology. According to the Chinese medicine of "xiang thinking", the theory of "dirty blood hurting veins" was systematically put forward, pointing out that the abnormal substances and the normal matters of overload in the blood contribute to the dirty blood. These substances or matters mainly hurt vascular intima, especially the arterial intima, with the help of the blood pressure and blood flow. The main pathological process is an inflammatory response characterized by defense and repair. The blockage of blood flow resulted from dirty blood can lead to a series of chronic organ ischemic lesions. Given that a major portion of the dirty blood originated from the Qing or normal metabolic product, so the limit of the Qing, transformation of the Qing, excretion of the waste, and lowering the blood pressure are the main strategy to prevent vein from injury by dirty blood. The theory also gives clues to search the direct causes of cardiovascular diseases on traditinoal Chinese medicine.