Cerebral small vessel disease is a series of clinical, imaging and pathological syndromes caused by various etiologies affecting the arteries, capillaries, venules in the brain. The common causes of cerebral small vessel disease include arteriolosclerosis, cerebral amyloid angiopathy, hereditary cerebral small vessel disease, inflammation-and immune-mediated small vessel disease, venous collagen disease and other small vessel diseases. Of these, age-and hypertension-related cerebral small vessel disease and amyloidosis cerebral small vessel disease are the most common types. The pathophysiological mechanism and clinical manifestations of cerebral small vessel disease are complex. One-fifth of ischemic strokes and the vast majority of nontraumatic parenchymal hemorrhages are due to cerebral small vessel disease. In addition to stroke, patients with cerebral small vessel disease are more often characterized by chronic progressive neurological impairment, which is an important cause of cognitive decline and functional disability in the elderly, and has become one of the important public health problems affecting the quality of life of the elderly. Focusing on cognitive impairment-related diseases, a large number of clinical studies have shown that Tongxinluo capsule has a dual neurovascular protective effect, which can increase the Mini-Mental State Examination (MMSE) score and activities of daily living (ADL) score of patients with lacunar cerebral infarction combined with vascular cognitive impairment, reduce fibrinogen (FIB) concentration, improve whole blood viscosity, improve blood viscosity and FIB level, improve activities of daily living and accelerate intellectual recovery in patients with VD; It can also reduce the levels of ET-1 and homocysteine in AD patients, reduce the whole blood viscosity and thus improve the microcirculation in the elderly, increase cerebral blood flow, increase the scores of MMSE and ADL, improve the intelligence of patients, improve memory disorders and language disorders. Meta-analysis of 3458 patients in 40 published clinical literatures of Tongxinluo capsule both domestically and internationally confirmed that Tongxinluo capsule had the effect of promoting the recovery of neurological function, and was safe without adverse reactions. This project is a randomized, double-blind, placebo-controlled multicenter clinical study to investigate the clinical efficacy and safety of Tongxinluo capsule in the treatment of cerebral small vessel disease. A total of 1052 subjects who met the subject screening criteria are planned to be enrolled, with 526 patients in the test group and 526 patients in the placebo group. The study is conducted using a central randomization method. For the patients who met the inclusion criteria after examination, they are logged into the Interactive Web Response System by their site, entered the relevant information, and randomized and assigned drugs automatically by the central server according to the ratio of 1:1. Once enrolled, all patients receive the study drug (Tongxinluo or placebo) at 4 capsules/tid for up to 12 months. The study is planned to be conducted at approximately 50 centers across the country using central randomized competing enrollment.