Absorption coefficient has important scientific significance,acting as not only an important part of the inherent optical properties of waters,but also as the physical basis to build a bio-optical model.In this paper,dominant types of waters' absorption coefficient were classified and analyzed with the method of "Remote Sensing of Ocean Colour in Coastal,and Other Optically-Complex, Waters (IOCCG) "based on the in situ measurements during the period of 2008 2011 of three freshwater lakes (Lake Poyang, Lake Taihu and Lake Chaohu) in the middle-lower reaches of the Yangtze River.Because of the spectrals of a_d (non-pigment particles absorption),a_ph (phytoplankton pigment absorption),a_g (colored dissolved organic matter absorption) are greatly different, we consolidated the dominant types of IOCCG as type a_d-g and type a_ph-related.Results show that: 1) In autumn,the dominant type of Lake Poyang,Lake Taihu and Lake Chaohu is a_d,a_d-a_g,a_d-a_ph-a_g,respectively;In summer,Lake Poyang and Lake Taihu are co-lea_ded by two dominant types,they are a_d,a_d-a_g and a_d-a_ph-a_g,a_d-a_ph.2) Both dominant-type in summer, autumn of Lake Poyang and in autumn of Lake Taihu are a_d-g;however,Lake Taihu in summer and Lake Chaohu in autumn have the a_ph-related dominant-type.3) For the Gons and Gitelson algorithms and their assumptions,the applicability conditions are found inconsistency in different lake water and different dominant types.