Side-scattering lidar based on CCD, which is not affected by geometrical factors, is a powerful tool for ground layer aerosol detection. The detection technology at night is mature. Since moonlight and starlight in the background light are much weaker than the sunlight, the signal-to-noise ratio is very low when we detect ground layer aerosol during daytime using the detection technology used at night. In experiments, lens with a small field of view and a narrowband filter is selected. Meanwhile, correcting narrowband filter transmittance, reducing single exposure time, and multi-average-exposure are applied to improve signal-to-noise ratio effectively. The daytime case shows that the aerosol backscattering coefficient profile from side-scattering lidar is consistent with that from backscattering lidar in the range from 0.75 km to 1.5 km. The correctness of side-scattering lidar detection under 0.75 km is also verified. Continuous 37 h profiles of aerosol backscattering coefficient of Hefei near ground region are calculated, and the analysis combined with temperature and PM2.5 mass concentration is conduct. The results indicate that the improved side-scattering lidar detection technology is correct and feasible.