Abstract: The estimation of ocean organic carbon stocks plays an important role in researching on the process of carbon cycle and predicting climate changes. The ocean organic carbon stocks can be estimated using remote sensing reflectance, water optical properties and other parameters. According to the properties of water in the East China Sea, the estimation results of several algorithms of organic carbon were compared in this paper. Combining with the vertical distribution models, a complete estimation model of organic carbon in the East China Sea was obtained. Based on the remote-sensing reflectance, the temperature data and the salinity data of 2010 provided by MODIS and Argo, the organic carbon stocks in the East China Sea were estimated and analyzed according to seasons. The results show that the organic carbon stocks of the all water column in the East China Sea in 2010 are between 1.530×10¹⁴ g and 2.125×10¹⁴ g, and the organic carbon stocks of the euphotic layer are between 4.119×10¹³ g and 7.980×10¹³ g. The organic carbon stocks in the all water columns are high in winter and low in spring, while organic carbon stocks in the euphotic layer are high in summer and low in winter. It shows a fluctuating upward trend from 2006 to 2015. The organic carbon stocks of the East China Sea is estimated. It provides a method for the determination of ocean carbon stocks in China in the future.