Biomass burning (BB) activities emit a large quantity of water-soluble organic carbon (WSOC) aerosols into atmosphere, resulting in adverse effects on air quality, climate change and human health. In order to investigate the influences of BB activities on mass concentrations and light absorption of WSOC aerosols, PM_(2.5) samples were collected from May 2013 to January 2014 in Sanjiang Plain, Northeast China. The concentrations of levoglucosan, organic carbon (OC) and WSOC, as well as light absorption of WSOC were also analyzed. The sampling days were categorized into BB and non-BB (NBB) periods based on the concentrations of determined levoglucosan. During the BB period, the concentration of PM_(2.5), WSOC and levoglucosan were 10 times higher than those of NBB days. Meanwhile, light absorption of WSOC increased by a factor of 13. The correlation index (R~2) between PM_(2.5) and A_(365a) increased from 0.34 on the NBB days to 0.98 on the BB events. Moreover, the strong correlation (R~2=0.91) between A_(365a) and levoglucosan were also found during the BB period, while that (R~2=0.09) was not observed during the NBB period. This indicated that BB contributed significantly to PM_(2.5) and emitted a large amount of brown carbon. Furthermore, we estimated that BB contributed, respectively, 74.6% and 46.2% to the total mass and light absorption of WSOC during the BB period. Although some uncertainty was existed in the estimations, our results demonstrated that biomass burning emissions have very important influence on both mass concentrations and light absorption of airborne WSOC aerosols at the sampling site.