Abstract: Thereturnspectrumoftheoceanichigh-spectral-resolutionlidar(HSRL)issimulatedwith a semianalytic spectral Monte Carlo (MC) method. The results show that the spectrumis similar to the single scattering spectrum at the water surface but broadens with the depthdue to multiple scattering. Therefore, if the non-spectral MC method that ignores the spectrumbroadening is used, deviations will be introduced into the HSRL retrieval, e.g., the effectiveparticulate 180 ° volume scattering function (backscatter) and lidar attenuation coefficient(attenuation). The simulation indicates that the backscatter and attenuation deviations are within10% and 2%, respectively, when the HSRL discriminator is the iodine absorption cell, andare within 3% and 1%, respectively, when the discriminator is changed to the field-widenedMichelson interferometer.