Two particulate organic carbon (POC) concentration retrieval models are developed with remote sensing reflectance at 745 nm (model 1) and 680 nm (model 2) based on the data collected near the Yellow River Estuary. The average percentage differences (APD) of the two models are less than 26%, and model 1 performs better. Accuracy evaluation is carried out with geostationary ocean color imager (GOCI) images and the measured data, and the average relative error is less than 30%. The developed models are used to analyze the temporal and spatial variation of POC concentration in the seawater near the Yellow River Estuary on the time scales of hour, day (for strong wind process) and season, respectively. The results show that the POC concentration is high in winter, and the POC concentration is low in summer. The peak value of POC concentration is found near the Bohai Bay. The variations of POC concentration are of the same order of magnitude under the three conditions, which shows that the obvious change of POC concentration may happen even in shorter time scale, while the seasonal mean effect is significant.