Abstract: Objective To understand the development of students' social anxiety in grade 3 during six years, and to explore the influence of various factors on students' social anxiety. Methods In 2009, 533 students in Harbin of 4 primary school in grade 3 filled in the questionnaire survey. The questionnaire included general situation, and the social anxiety scale for children(SASC).We conducted a questionnaire survey of these students for follow-up investigation using the same questionnaire in 2011, 2013 and 2015. Results The detection rate of students' social anxiety of the four-time test was 28.7%, 18.6%, 24.8% and 27.9%, and there was significant difference in them (χ²=12.000, P=0.007). In 2009-2015, the number of students always holding social anxiety was 10(2.8%). In 2011, 2013, 2015, the number of students newly occurring social anxiety was 33(13.0%), 58(20.1%) and 53(19.9%), and the number of students whose social anxiety disappeared was 69(67.6%), 36(54.5%) and 42(47.7%). In 2009 and 2015, the detection rate of students' social anxiety on parental quarrelling were higher than students in normal families(all P<0.05). In addition, there was difference in girls' social anxiety of different measuring time(F=2.699, P=0.049), and the girls' social anxiety was higher than boys' (F=11.273, P=0.001). There was significant difference in singletons' social anxiety of different measuring time (F=3.820, P=0.012). Non-singletons' social anxiety was higher than singletons' (F=4.269, P=0.040). Conclusions During the six years,development status of social anxiety was constantly emerging and remission,but there were still 2.8% of the students keeping social anxiety state. Gender, singleton and parental quarrelling can affect the development of students' social anxiety.