Mental retardation is also known as mental retardation and intellectual backwardness. Mental retardation is mainly manifested in low learning ability, social adaptation ability and self-care ability. The language skills, attention, memory, comprehension, observation, logical thinking and imagination of children with mental retardation lag significantly behind those of children of the same age. The World Health Organization’s definition of mental retardation includes three aspects: 1, intellectual function, IQ IQ is significantly lower than the general level of the same age, below the population mean of two standard deviations, the population mean IQ positioning is 100 points, a standard deviation is 15, the IQ of children with mental retardation, less than two standard deviations that is less than 70 points; 2, social adaptability has obvious defects, social adaptability is the ability of people to adapt to the external The ability to adapt to the environment and survive is also the ability to adapt to the needs of society, to achieve an independent life and fulfill social responsibilities, different developmental stages, the requirements for adaptive behavior are also different, preschool children’s adaptive ability is expressed in its age and the cognitive, gross motor and fine motor, sensory integration, language, response to people and self-care ability, school age is mainly expressed in academic achievement, after adolescence The main manifestations are academic achievement during school age, and after adolescence, academic, family relations, social, social and vocational achievements; 3. Low intelligence is a deficit during the developmental period, which generally refers to the age below 18. Low intelligence must have three aspects, with low IQ, low adaptive behavior, and a developmental period that is 18 years old with an age limit. A child is mentally retarded if his or her IQ is below 70% and also has significant deficits in social adaptation.