First of all, one should go to a specialized hospital to assess whether the intelligence is significantly lower than the level of people of the same age. Most patients can improve their intelligence through rehabilitation training in regular hospitals, learning culture and knowledge, and home rehabilitation training. Mental retardation caused by brain lesions can be improved after corresponding treatment. 1. Rehabilitation training in regular hospitals: When mental retardation is confirmed through hospital evaluation, patients should go to the rehabilitation department of hospitals as soon as possible and under the guidance of rehabilitation doctors, they should undergo rehabilitation training, including speech training and cognitive training, which can help to improve their mental ability. 2. Learning culture and knowledge: As the patient grows older, learning culture and knowledge and improving cognitive level can help to improve the patient’s intellectual backwardness. 3. Home rehabilitation training: At home, the patient can do cognitive training by using blocks, pictures, reading newspapers, etc. in the company of family members. 4. Treatment of brain lesions: For mental retardation caused by meningioma, hydrocephalus, etc., the problem of mental backwardness can be improved through regular treatment by doctors. However, there is no effective treatment for some of the mental retardation caused by chronic brain lesions, and cholinesterase inhibitors and other medications can be used to alleviate the symptoms. When a patient is intellectually backward, he or she should go to a regular hospital as early as possible for evaluation and formulation of a rehabilitation training program, which can maximize the improvement of the patient’s intelligence through early and active intervention and rehabilitation.