Abstract: Chromophoric dissolved organic matter (CDOM) is the fraction of DOM pool that absorbs light in both the ultra violet and visible ranges. It plays an important role in marine carbon cycling. Based on field investigation in the Bohai Sea and the North Yellow Sea in July and December 2019, we analyzed the sources of CDOM and its spatiotemporal variations and controls. Sources of CDOM in the Bohai Sea were dominated by river runoffs and in some subareas modulated by in situ production; whereas the latter played a more important role in the North Yellow Sea. The abundance, molecular weight and humic-like components of CDOM decreased from nearshore to offshore and were generally higher in the Bohai Sea than in the North Yellow Sea. Protein-like component showed a patch-like distribution and displayed little difference between the two seas. The absorption properties of freshly-produced CDOM in summer varied in wide ranges in the Bohai Sea and the North Yellow Sea. After long-time sunlight exposure and microbial degradation from summer to winter, they were consumed out or partially converted to recalcitrant DOM so that the absorption properties of winter CDOM pools varied in a narrow range.