The investigators hypothesize that electromagnetic therapy (EMT) could produce greater improvement on Autism spectrum disorder (ASD) compared to the waitlist control. To test this hypothesis, a pilot randomized waitlist-controlled trial is designed to achieve the 2 aims: 1. To evaluate the efficacy of EMT in improving children with ASD as measured by Childhood Autism Rating Scale (CARS) by comparing the change in CARS scores from baseline to week 12 between the two groups. 2. To assess the safety of EMT by comparing the number of participants with adverse events, number of participants withdrawn and reasons of withdrawal in treatment group with those in the control group. A pilot randomized waitlist-controlled trial is designed. A total of 30 children aged 3-12 years with a principal diagnosis of ASD will be recruited. They will be randomly assigned to Care-As Usual (CAU) and CAU+EMT groups (n = 15 each group). Participants on the CAU+EMT group will receive a total of 30 sessions of EMT within 12 weeks (2 - 3 sessions/week).Those who are initially assigned to CAU group will receive EMT for 12 weeks after they complete the trial. The post-trial treatment will serve as a compensation for their participation.