Utilizing a large sample， this study aimed to explore the distribution characteristics and influencing factors of immunoglobulin （Ig） IgG， IgA and IgM during long-term high-intensity training for elite athletes in Guangdong Province， and to establish the corresponding percentile reference values and ranges. A total of 2 274 elite athletes from 35 sports events were recruited from 2012 to 2019. The

t

-test of one sample was utilized to compare Ig levels between athletes and the general healthy population， while the

t

-test of two independent samples compared Ig levels across different gender and types of sports. Additionally， one-way ANOVA was used to compare Ig levels across different sports event-groups， seasons， and preparation years for National Games. The generalized estimating equation was applied to analyze the factors affecting athletes' Ig levels. The skewness-median-coefficient of variation method established the percentile reference values and ranges for Ig levels. The results indicated that the levels of IgG （

P

<

0.01）， IgA （

P

<

0.001）， and IgM （

P

<

0.001） in athletes were （11.50±2.20）， （1.92±0.66）， and （1.30±0.58） g/L respectively， significantly lower than those in the general healthy population. The levels of IgG and IgM in male athletes were significantly lower than those in females （

P

<

0.001）. Athletes dominant in physical sports exhibited significantly lower IgG levels compared to those dominant in skill-based sports （

P

<

0.01）. Distinct variances were observed in IgG （

P

<

0.001） and IgM （

P

<

0.01） levels among different sports event-groups， and in IgG levels across various seasons （

P

<

0.05）. The results also indicated that gender （

P

<

0.001）， sports event-groups （

P

<

0.05）， and seasons （

P

<

0.01） were key factors influencing IgG levels， with both gender （

P

<

0.001） and sports event-groups being key influencing factors of IgM levels. Furthermore， the 95% reference range for athletes' IgG， IgA， and IgM were 7.34-16.56， 0.82-3.47， and 0.46-2.91 g/L respectively； for males， they were 7.34-15.71， 0.88-3.47， and 0.46-2.27 g/L， and for females， 7.96-16.56， 0.82-3.36， and 0.63-2.91 g/L. The research suggests that more attention should be paid to the individual evaluations of different gender and sports events， and the impacts of climatic conditions and temperature when monitoring of immune function status of athletes. The percentile reference values and ranges of IgG， IgA， and IgM levels obtained in this study can be accounted in accurately assessing the immune function status of athletes， providing scientific evidence for monitoring training， evaluating the immune system， and regulating nutrition in athletes.