The colored dissolved organic matter (CDOM) is one of the three elements of ocean color remote sensing, and remote sensing monitoring of CDOM of the case-Ⅱ coastal water has always been a hot but difficult topic in the world. Based on the survey data of the two voyages in Zhanjiang harbor from 2016 to 2017, the spatial-temporal characteristics of the optical properties and the source of CDOM in the waters of Zhanjiang bay were discussed. The results showed that: In terms of seasonal changes, it manifest that CDOM absorption coefficient (ag(355)) and spectral slope (S275~295) in the surface waters of the harbor in autumn were greater than that in summer. In terms of spatial distribution, the ag(355) of the thalassic surface and bottom layers of summer basically showed a decrease trend from the north to the south and from the west to the east, meanwhile the S275~295 presented a patchy distribution in the horizontal space generally. Moreover, chlorophyll a concentration and turbidity were relatively high with a variation range from 1μg/L to 5 μg/L of chlorophyll a concentration and a range from 5 NTU to 70 NTU of turbidity. For another, dissolved oxygen concentration is relatively low which ranges from 3 ml/L to 5 ml/L in the bay. According to the comprehensive analysis of CDOM absorption coefficient, spectral slope, chlorophyll a, dissolved oxygen and turbidity, we can draw a conclusion that the CDOM in the Zhanjiang bay waters mainly comes from terrestrial input and phytoplankton on-site production in the summer and autumn, the sediments resuspension has a certain contribution to the source of colored dissolved organic matter in the autumn. Furthermore, the concentration of colored dissolved organic matter was negatively correlated with DO in the two seasons accompanying a certain indication function for water pollution and eutrophication.