The optical properties of the semi-closed Bohai Sea are complex due to significant terrigenous influence.The high temporal resolution data from geostationary ocean color imager (GOCI) makes it possible to explore thetemporal and spatial variability characteristics in the Bohai Sea, especially on the hourly temporal scale. A remotesensing algorithm is developed to retrieve the total absorption coefficients at 412, 443, 555 nm in the Bohai Sea basedon the GOCI band ratio of remote sensing reflectance. The algorithm is validated with independent field data. Thecorrelation coefficient between the retrieved and measured data is higher than 0.8, the average absolute percentagedifference (APD) is less than 13%, and the median absolute percentage difference is less than 9%. The performanceis better than that of previous typical algorithms (improvement over 10%). Based on the independent field-satellitematch-up data, the APD between the retrieved and measured data is less than 35%. On the basis of the GOCI image (May 4th，2015) and the new model, the spatial and hourly variation characteristics in the Bohai Sea are discussed.The results show that diurnal variability magnitude is mainly 0.2~0.3 m^-1, and the maximum can reach 0.8 m^-1. Highdiurnal variability values are found mainly in the Liaodong Bay, the Bohai Bay and the Laizhou Bay. The totalabsorption coefficient is analyzed together with tide data, and the variations are generally consistent with thecorresponding tidal height variations in the Liaodong Bay and the north of the Bohai Bay, though the minimal totalabsorption coefficient appears about 0~1.5 h later than the lowest tide moment. The total absorption coefficientshows significant negative correlation with tide height in the west of the Laizhou Bay. The total absorption coefficientand tidal height have no obvious correlation in the south of the Bohai Bay and the east of the Laizhou Bay.