For evaluating the effects of in-service training about primary school teachers how to guide ADHD children, this study adopted a pre- and post-test design which chose 53 primary school teachers from Beijing as the experimental group and 59 primary school teachers as the control group. The teachers of experimental group were trained for 6 times in twelve weeks, and the teachers of control group didn’t receive any intervention. Then the questionnaires were used to evaluate the effects. This sharply contrasts with the teachers of control group, the ability about how to deal with ADHD children of the teachers in the experimental group enhanced greatly: 1) the knowledge level about the causes, symptoms and how to treat the ADHD children was increased obviously; 2) instead of the negative beliefs about ADHD children, more positive beliefs and self-efficacy emerged in the teachers of experimental group; 3) the teachers obtained more tutoring strategies for ADHD children, and they enhanced the ability greatly in the home-school communication, positive reinforcement, personalized behavioral intervention and academic intervention.