The detection of atmospheric backscattering signals using fluorescence from an iodine blocking filter in high-spectral-resolution lidar was studied experimentally. The efficiency of detection is determined by the fluorescence quantum efficiency and the optical efficiency of collecting fluorescence. The quantum efficiency was estimated to be ${\sim}{0.08}$ from the measured fluorescence lifetime of 0.18 µs and the radiative lifetime of 2.3 µs estimated from the literature. The efficiency of collecting fluorescence was low (${\sim}{0.008}$) in the current system. Measurements of atmospheric backscattering were performed, and it was confirmed that the method actually detected the Mie scattering component of the signal.