Observation on reproductive ecology of Common Teal(Anas crecca)was conducted in breeding season in South-central Heilongjiang Province from 2007 to 2009 and totally 4 nets were located.Common Teal arrived the study area from late March to early April and leaving at early October.The residence period of the four pairs observed was about six months.Paired Common Teal build their nest in early May and completed it in 5.5 ± 1.0 days(n=4).The nests were built in the grassland and bushes near the water areas with relatively simple structure.Females laid their first egg in 3.25 ± 0.50 days after nests were completed.The clutch size was 9.80 ± 2.21 eggs in average(range 7 to 12,n=4).The mean of egg weighted 28.70 ± 0.72 g,n=39.Females initiated incubation immediately after they laid the last egg.Incubation period lasted 22-26 days,averaged 24.25 ± 1.17 days(n=4).The hatching success rate was 79.5% ± 29.98% in average.Chicks were precocious and it took 29.75 ± 1.70 days for the nestlings to grow up.