Need to play in the living of children is accounted as their deepest and most fundamental natures that can be considered same as its physical needs. According to Mariana Monteh Souri, Italian trainer in the field of education and training, one can nurture and promote the self- confidence of a healthy personality and self- training by playing. She also believes that ethical and social disadvantages of children may be removed or reduced by play and bases for loving the job and social activity will be stabilized by playing.This study aims to investigate the role of play in development of social skills of children in three groups, kindergarten (3- 5 years old), pre-school (6-7 years), and school (8 - 12 years).The sample size of this study was 720 pupils obtained using stratified random sampling from 5 districts of Teheran. According to the subject of this study, besides type of play, with type of toys and time of play, this study investigated the development of social skills of children focusing on two factors, intelligence profile and social skill and its data analyzed using MANOVA Two Way analysis of variance statistical model. The test of hypotheses indicated that there is significant difference between dependent variables, “social skill” focusing on the group (kindergarten, pre-school and school); and finally by comparing the results of this study with related history in and out of country, it has been concluded that play, play therapy and even type of toy will increase the social skills of children.