Abstract: MR children participated in this research project.Time-sampling method was used to make the data-collection in classes and in free plays in a dynamic way. The subjects's categories of behavior in classes and 7 categories of behavior in free plays were analysed according to different Kindergarten and levels of mental retardation.The results showed:numbers of children in one class,different teaching strategies,levels of mental retardation,etc.were correlated with MR children's behaviors. Discussions on methodology of data-collection,the relationships between different Kindergarten with MR children's behaviors,the relationships between different levels of mental retardation with MR children's behaviors,and the high frequency of self-amusement activities were made.Finally,based upon the fidings the author gave some suggestion on teaching stretegies to special education teachers.

Key words: mental retarded child(MR child), levels of mental retardation, time-sampling method, behaviors