Objective: To understand the prevalence and influencing factors of scoliosis among primary and middle school students in Shanghai, so as to provide reference for the prevention and control strategies of scoliosis in children and adolescents. Methods: From September to December 2021, a total of 4 531 students from grade four of primary school to grade three of junior high school from 16 primary and middle schools in 4 districts of Shanghai were selected by multi stage stratified cluster sampling to carry out scoliosis screening and questionnaire survey. Independent sample t-test, Chi-squared test, Fisher s exact probability method and nonparametric Mann Whitney U-test were used for statistical analysis, and multivariate Logistic regression was used to analyze the influencing factors of scoliosis. Results: The on the spot detection rate of scoliosis abnormality was 7.4% and the prevalence was 2.2%, mainly for thoracolumbar scoliosis (60.4%) and the scoliosis angle of 10° -<20°(88.1%). The results showed that the detection rate of scoliosis in boys was 1.6% and in girls was 3.3%, with a statistically significant difference ( χ 2=11.84, P < 0.01). There were significant differences in weight and BMI between scoliosis students and students with negative initial screening( t = -3.77, -5.30, P <0.01). And there was a statistically significant difference in the detection rate of scoliosis with different frequency of classroom seating arrangements ( Z =2.02, P <0.05). The results of multivariate Logistic regression showed that the risk of scoliosis in girls was higher than that in boys ( OR =1.87, 95% CI =1.21-2.88). BMI ( OR =0.89, 95% CI =0.83-0.95) and frequency of classroom seating arrangements ( OR =0.49, 95% CI =0.25-0.93) were correlated with lower rate of scoliosis. After stratification by sex, the frequency of classroom seating arrangements ( OR =0.26, 95% CI =0.10-0.67) in boys and the educational stage ( OR =2.35, 95% CI =1.26-4.41) in girls ( P <0.05) was correlated with higher rate of scoliosis, while BMI ( OR =0.86, 95% CI =0.79-0.94) in girls were correlated with lower rate of scoliosis. Conclusion Regular screening of scoliosis is an effective method for early detection of scoliosis. Girls in junior high school and low BMI should be paid close attention to. According to the occurrence and influencing factors of scoliosis, comprehensive prevention and control based on family, school, society, and other aspects can be carried out.