We live-trapped two Niviventer confucianus populations from March to November of 2010 in Thousand Island Lake region using the capture-mark-recapture (CMR) method. We used Jolly-Seber method, modified Lincoln index method, Schnabel method and minimum number of animals alive (MNA) method to estimate population sizes of Niviventer confucianus, and discussed the applicability of these estimators in white-bellied rats on land-bridge island. Our results showed that there was no significant difference between Jolly-Seber method and modified Lincoln index method. We considered that modified Lincoln index method was more suitable for estimating the population quantity of Niviventer confucianus in the land-bridge island. The study can provide basic data for the future study of population ecology of rodent in the land-bridge island.