Childhood autism is a subtype of pervasive developmental disorder, prevalent in males, that begins in infancy and early childhood and manifests mainly with varying degrees of speech and language developmental disorders, interpersonal difficulties, narrow interests and stereotyped behavior. About 3/4 of patients have significant mental retardation, and some children have good ability in a certain area against a background of general intellectual backwardness. Language and communication disorders are important symptoms of autism and are the main reason for most children to be seen. Most children with autism have delayed or impaired language development, usually still not speaking at the age of two and three, or regression in language after normal language development, expressive language until the age of two to three, gradually decreasing with age or even completely lost, lifelong silence or limited language use in rare cases. They have some degree of impairment in their ability to perceive and use language. 2. Patients with social interaction disorder cannot establish normal interpersonal relationships with others. At a young age, they show no eye contact with others, have poor expressions, lack expressions or gestures expecting hugs and caresses from parents and others, and do not have pleasant expressions when enjoying caresses, and even refuse hugs and caresses from parents and others. They do not distinguish between close and distant relationships and treat their relatives the same way as they treat others. For example, the patient spends a lot of time alone in kindergarten and does not like to play with peers; when he/she sees some children playing games together, he/she has no interest in watching or participating. 3. Patients are not interested in the games and toys that normal children are interested in, but prefer to play with non-toy objects, such as a bottle cap or observing a rotating fan, and can continue for tens of minutes or even hours without boredom. The patient is not interested in the main features of the toy, but is very concerned with the non-main features: the patient stubbornly demands that the routine remain the same, such as the time of going to bed, the covers they cover, and the same route they take when they go out. If these activities are stopped or the behavior pattern is changed, the patient expresses significant unpleasantness and anxiety, and even defiant behavior. Patients may have repetitive stereotyped actions, such as repeatedly clapping their hands, spinning in circles, licking the wall with their tongues, stamping their feet, etc.4. Intellectual impairment Among autistic children, the level of intellectual performance is very inconsistent, with a few patients in the normal range and most patients showing varying degrees of intellectual impairment. Domestic and international studies have shown that about 50% of autistic children are found to have more than moderate intelligence deficiency (IQ less than 50), 25% have mild intelligence deficiency (IQ 50-69), 25% have normal intelligence (IQ greater than 70), and those with normal intelligence are called high-functioning autism.