Objective:To study the effect on the odontotherapy dentist communicate with his preschooler patient before operation through clinical experiment.Method:Random selection the preschooler patients(3-6 years old) who come to our pediatric dentists to cure their caries,no matter boy or girl,divided them into two groups,one is experimental group,one is control group.In experimental group,the dentist should full communicate with his patient before routine treatment ; In control group the dentist adopt the routine treatment directly.Record the little patients appearance in the two different therapeutic process.Result:80% little patients show good performance in experimental group,who are active to coordinate with their dentist,and want further consultation with their dentist initiatively.Only 18% little patients show good performance in control group,but 62% little patients show bad performance,even cant be treated routinely.