Abstract :
At this time in diagnosing autistic disorder in children is done manually and simple. The drawback of this system is a patient always need an expert or doctor to find out what happened to autistic disorder is based on the perceived symptoms of a patient. So it needs a system that can transfer the knowledge of an expert or a doctor, he built an expert system application that can help the work of an expert in handling the problem with certainty factor method. This expert system by using certainty factor can help one to diagnose the type of autistic disorder in children with symptoms that appear without going through medical tests, and provide solutions to the diagnosis. The value of CF is determined by the total number of matches between symptoms and disorders as well as the value of CF for each rule in the rule diagnostics.