ABSTRACT
Objective Network Scale-Up Method (NSUM) was used to estimate the Personal Network Size (C) of college students in Beijing and the size of men who have sex with men (MSM).Methods A survey was conducted on Beijing college students to estimate the personal network size (C) through NSUM and then using the back-estimating and attitude adjustment to correct C value and the size of the target population.Results The mean of C among Beijing college students was 97 and the differences of C between different majors and different grades were both statistically significant.Among Beijing College students,3.96％ of them identified themselves as MSM,with the number as 16 260.Conclusion Using the NSUM to estimate C of Beijing college students and size of MSM seemed to be credible which worth popularized.