Temperature could have a causal effect on avian timing of reproduction,and effects of climate change on avian life-history traits are the main focus in ecological research. During two breeding seasons (April) in 2014 and 2015,effect of temperature on breeding date and nesting success of barn swallow (Hirundo rustica),a tropical population in four villages of Lingao,Hainan, south China,was investigated. The results showed that barn swallows delayed their timing of reproduction in 2015 compared to their breeding date in 2014,and breeding nest use by swallows in 2015 was significantly lower than that of 2014 (X~2 = 70.37,P<0.001). The mean minimum temperature of April in 2015 was 2 ℃ lower than in 2014 (t = 0.794,df = 71,P = 0.442),and low temperature and local temperature fluctuations had negative effect on the breeding date of barn swallows. However,there was no significant difference in clutch size (t = 0.670,df = 87, P = 0.505) and nesting success (t = 0.794,df = 71,P = 0.442) between the two breeding years. In conclusion,we found that even in the tropical Hainan,low temperature and local temperature fluctuations had negative effect on breeding date of barn swallows,but not on their breeding performance.