(1) Main aim: Effect of combining tDCS and behavioral intervention on behavioral problems in children with autism spectrum disorder, Goals: A- Comparison between the combining tDCS and PRT with placebo tDCS and PRT group on behavioral problems in 10 up to 16-year-old-children with autism spectrum disorder. (2) Design: This study is a randomized single blind clinical controlled trial. (3) Setting and conduct: Study population consisted of children with autism spectrum disorder are referred to clinical centers of Hamadan university of medical sciences that 30 person divided in 2 groups included tDCS with Pivotal response treatment(PRT), placebo tDCS and PRT will be randomly selected. Inclusion criteria: Diagnosis of autism spectrum disorder based on the psychiatrist's interview or neuropediatrist According to DSM-5 criteria and using Gilliam autism rating scale(GARS). Be at least 10 and up to 16 years, weigh at least 5 Kg, Mental age be at least 18 months. Exclusion criteria: The people with acute and serious mental disorders such as schizophrenia, etc, People with other medical illnesses such as head injuries, Neurologic Diseases, A history of seizure, auditory and visual deficit. Intervention and time: Phase 1- In this phase all patients will receive PRT for 8 weeks. after 8 weeks, all patients will divide in 2 groups: Group 1 will recieve tDCS 10 sessions per 2 weeks and group 2 will receive placebo for 2 weeks. in Phase 2, the tDCS intervention will discontinue and PRT will continue on both groups for 2 weeks . All patients before and after the treatments will assess by Aberrant behavior checklist(ABC) and Vineland adaptive behavior test. Outcome variables: behavioral problems, adaptive functions.