Previous studies have confirmed that Autism Spectrum Disorders (ASD) have difficulties recognising emotions from facial expressions. Some scholars investigated the characteristics of visual scanning and behavior of ASD’s expression cognitive, and considered that local processing has taken in the ASD’s expression cognitive. Other scholars considered that information characteristics of expression images can influence the expression cognitive, but corresponding empirical studies are absent. By weakening information characteristics of expression images, visual scanning time of different expression images for 12-16 year-old autistic children are investigated, and the influence of changing information characteristics of expression images on the visual scanning are explored, and the mechanism of expression processing of autistic children are discussed in detail. Four kinds of expression images namely happy, sad, angry, fear are dealt by software photoshop to three effects, black and white facial images, basal highlight and angles lines, with decreasing relation of expression information characteristics. Expression images present by Tobii Studio and the duration is set as five seconds. We collect visual scanning time of expression images by Tobii T120 eye tracker. The experiment includes two parts: the first part is analyze the visual scanning time of whole face by repeated measures design of 4 (happy, sad, angry, fear) *3 (characteristic facial expression, information, information characteristics weaken weakened two), and the second part is analyze the visual scanning time of eye area and mouth area by repeated measures design of 4 (happy anger, sadness, fear), *3 (characteristic facial expression, information, information characteristics weaken weakened two) *2 (mouth, eye area). The experimental results show that: (1) the whole face scanning times of the four kinds of expression images of autism are different, the whole face scanning time of happy and sad facial expression has no significant difference（p>0.05）, and both higher than that of anger and fear(p<0.01), and the whole face scanning time of angry is higher than that of fear(p<0.01); (2) differences exist in visual scanning mode of different facial expressions for children with autism, no significant difference of eyes and mouth scanning time can be detected of happy and sad facial expression(p>0.05), while the mouth scanning time is quite longer than that of the eyes of fear and anger facial expression (p<0.01); (3)heap map show that weakening information characteristics can affect the face expression visual scanning of children with autism. With increasing the weakening degree of facial expression images, the scanning time of mouth increase while decrease for eyes. By analyzing the experimental results, conclusions are shown as follows: (1) For 12-16 years old children with autism, local processing characteristics does not appeared in the visual scanning at happy and sad expression, while for anger and fear expression images, local processing are appeared; (2) Changing of expression information characteristics influence the visual scanning of facial expression. With weakening of expression information, the visual attention of autistic children directing more to the mouth area; (3) Children with autism in the expression cognitive process is affected by characteristics of the facial expression information, and they can adjust the visual attention according to the changing of expression information characteristics to get full cognitive of expressions, and shows the conscious ability to use information processing strategies.