In order to explore the role and expound the mechanism of rehabilitative brain computer interface (BCI)-based training (referred to as the Walk Again Neurorehabilitation protocol) in neurofunctional reconstruction in acute phase of cerebral infarction, the investigators choose non-invasive BCI to study lower limb function of patients with acute cerebral infarction. The investigators evaluate lower limb function, the influence on the central brain functional network and relevant immuno-inflammatory indicators, so that the investigators can explore the therapeutic effect and mechanism in the acute phase of cerebral infarction and provide theoretical bases and feasible guidances for the treatment of post-stroke dyskinesia.

The participants will be randomly divided into experimental group and control group. The experimental group will receive BCI-based lower limb functional training, 30 minutes per time, 5 times per week, with a 4-week training period; the control group will only receive routine lower limb training, with the same treatment frequency, intensity and duration. Statistical analysis will be performed to compare the relevant evaluation indexes of the experimental group and the control group after treatment and 90 days. In this study, the investigators will use Lower Extremity Fugl-Meyer Assessment (LE-FMA) to comprehensively evaluate the function of lower limbs, Functional Ambulation Category Scale (FAC) and 10-meter walking test (10MWT) for walking ability, modified Barthel index (MBI) for daily living abilities, functional magnetic resonance imaging（fMRI）and near infrared functional brain imaging (NIRS) to evaluate brain function and network reconstruction, the translocator protein(TSPO)-positron emission tomography (PET) and blood immune inflammation indicators to evaluate systemic and intracranial immune status.

Inclusion Criteria:

1. The diagnosis of cerebral infarction conforms to the diagnostic criteria of "Chinese guidelines for diagnosis and treatment of acute ischemic stroke 2018".
2. 35 ≤ age ≤ 60 .
3. Onset (last-seen-well) time to randomization time from 24-72 hours.
4. First onset.
5. The lesion is assessed by MRI as a single subcortical infarction of the anterior circulation.
6. 5 ≤NIHSS≤15 (and 1 ≤6a/b≤3 ).
7. 1 ≤FAC functional walking scale score ≤ 3.
8. Signed informed consent from subject or legally authorized representative.

Exclusion Criteria:

1. Unstable vital signs.
2. Progressive stroke.
3. Patients have received intravenous thrombolysis or endovascular treatment.
4. Cardiogenic cerebral embolism.
5. Presence of moderate or higher vascular stenosis or vulnerable plaque based on Imaging assessment.
6. With other diseases of the nervous system.
7. With serious diseases of other systems (severe circulatory system, respiratory system, motor system) and other diseases unsuitable for training, such as atrial fibrillation, heart failure, lung infection, severe liver or kidney insufficiency, lower extremity venous thrombosis.
8. Lower limb dysfunction caused by other reasons, such as fracture, lower limb deformity, etc.
9. With contraindications in imaging examinations, such as metal implantation, fear of claustrophobia, and severe obesity.
10. Patient who cannot cooperate with training, such as mental disorders, cognitive dysfunction, Mini-Mental State Examination (MMSE) <21 points, etc.
11. Other reasons: alcoholism; pregnancy; skull defect; indwelling urinary catheter; vision defects affect training, etc.