Introduction: One of the greatest popular neurodevelopmental disorders global is autism spectrum disorder (ASD), which is described by language postponement, reduced communication interactions and repetitive patterns of behavior produced by ecological and genetic factors. So that, autism is linked with great cost to families, individuals, societies and government. This study aimed to identify the effect of health instructions guidelines on improving knowledge and practices of mothers regarding care of their children with autism. Methods: This quasi-experimental study was conducting at Ali Al -Tamimi Center for Autism in Oniazah at Qassim region in kingdom Saudi Arabia. A convenient sample of 60 mothers and their children with autism. Data was collected through three tools were used to collect data include structured interview questionnaire consisted of two main parts include socio-demographic data related mothers, personal characteristics of the children, Mothers' knowledge regarding autism and mother practice regarding care of children with autism. Results: The result of the study displayed that the post-test of knowledge and practice among mothers of children with autism were significantly adequate when compared to pre-test. The study finding revealed that Educational Program was effective in enhancing the knowledge and good practice among mothers regarding care of children with autism. Conclusion: the educational program statistically significantly improved the knowledge and practice of the studied mothers. Recommendation: Emphasize the significance of carrying out educational programs to increase knowledge, practice and improve the coping designs of the family caregivers taking children with autism.Keywords: autism spectrum disorder (ASD), ecological and genetic factors.