In our country there are about 60 millions mental health disorders children who need mental health care according large scope epidemiological investigation. But the child psychiatrists in China are not enough to serve so many kids. We hope that the abundant clinical experiences of senior child psychiatrists can help the younger doctors throughout the country by the advanced computer technology. It is a very interesting practice that uses the computer simulating the human being brain. In research selecting suitable neural network structure is very important too. Suitable neural network structures will bring less error to diagnosis system. The diagnosis system of child mental health disorders can diagnose 61 kinds child mental health disorders. It includes more than 95% child mental health disorders. After diagnosis, the computer will give a treatment method suggestion. Comparing the diagnosis by computer with the senior child psychiatrists the consistent rate is 99%.