This paper reviews the study progress of lake optics including the theory framework,study methods,bio-optical proper-ties,chromophoric dissolved organic matter (CDOM) biogeochemical cycle,relationships between light and phytoplankton, optical effect of sediment resuspension,lake water color remote sensing.The theory framework of lake optics includes absorption,scatter-ing and attenuation of four optically active substances (pure water,CDOM,phytoplankton and tripton) and the water radiation transfer equation.A series of methods including the field investigation of spatial-temporal pattern of lake optics,the successive ob-servation of hydrodynamic and algal bloom processes, high frequent observation of bio-optical parameters, the experiment controlled and simulated are presented.The spatial-temporal patters of particles absorption, scattering, backscattering, diffuse attenuation co-efficients and euphotic depth in different lakes are obtained,and the interrelationship of particles absorption,scattering,backscat-tering,diffuse attenuation coefficients,euphotic depth and the concentrations of optically active substances are presented.CDOM spectral absorption coefficient,excitation-emission matrix fluorescence spectroscopy are used to characterize the spatial-temporal distribution,source,composition,removal and the contribution of CDOM to ultraviolet radiation attenuation.There is also consid-erable evidence that ultraviolet B radiation has an effect on phytoplankton growth and community structure.A vertically generalized production model of primary production is widely used to estimate phytoplankton primary production.Sediment resuspension has a significant effect on underwater light climate,which decreases transparency and euphotic depth,and further decreases phytoplankton primary production.Many algorithms are presented to estimate several water quality parameters including total suspended matter,chlorophyll-a concentrations and CDOM, phytoplankton absorption coefficients.These results are applied to satellite images for the monitoring of algal bloom in eutrophic lakes.Finally,the future developments of lake optics from the macro and microscopic perspectives have been expected.