The purpose to do the present research is the identification of the type and the number of noun modifiers in Persian students’ texts (students (10-12) in grades four, five and six) in which the number 9 area of Tehran was selected in purposive sampling and also 6 schools were selected by cluster random sampling. Then, the corpus of texts written by students in grades four, five and six was collected in these schools. In total, 9 classes in grade 4, 10 and 9 ones in grade 5 and 6 respectively were involved in this research and there were 889 students. According to Morgan table, 300 texts were randomly selected in which 2203 noun phrases were analyzed according to Dependency Grammar. Based on the findings, students (10-12) have produced noun postmodifiers (6/62%) by far more than noun premodifiers (2/45%) which indicates that the production of postmodifiers is much easier for the students in these grades and they have produced the genitive modifiers in eighth position (4/03%), attributive adjectives in seventh position (1/39%), in particular, numeral and superlative adjectives in third position (1/22%) respectively more than other positions. While the index in the sixth position (0/01%) has had the lowest average percentage. Students in grade 6 have had the highest average (12/44%), showing the older the students become, the more complex noun phrases they produce. The findings of this research along with identifying the amount of syntactic complexity of the children’s noun phrases shows the view of their language enhancement
