This paper describes methods for the correction of the atmospheric effects in the Landsat VIS/NIR imagery in relation to the retrieval of meaningful information about the ocean color, especially from Case-2 waters around Korean peninsula. Three atmospheric correction (AC) methods implemented and examined, using the TOA radiance or reflectance data, are 6S radiative transfer model, spectral shape matching (SSMM) and path-extraction methods. The results show that overall shape and magnitude of radiance or reflectance spectra of the atmospherically corrected Landsat VIS/NIR imagery by SSMM appears to have very good agreement with the in-situ spectra collected for clear and turbid waters, while path-extraction over turbid waters though often reproduces in-situ spectra, but yields significant errors for clear waters due to the invalid assumption of zero values for the black ocean pixels of the Landsat VIS/NIR bands. Because of the standard atmosphere with constant aerosols and models adopted in 6S model, a large error is possible between the retrieved and in-situ spectra. Validation suggests that accurate the retrieval of water-leaving radiance is not feasible with the invalid assumption of classical AC algorithms, but is feasible with SSMM.