Based on the side-scattering lidar equation and Mie scattering theory, the relational model of PM2.5 concentration and side-scattered light intensity is built, and a method for real-time monitoring near-ground PM2.5 concentration based on charge-coupled device(CCD) is proposed. A side-scattering lidar device is designed, which uses the laser with 532 nm wavelength as light source and CCD as the receiver. The side-scattering echo signal with scattering angle from 15° to 45° is measured with this device. The gray value matrix is extracted from the echo signal image, and the light intensity distribution in the echo signal image is analyzed. Compared with the measurement results provided by SHARP, a PM2.5 monitor from Thermo Fisher Scientific Company, the formula between PM2.5 concentration and total energy of three gray levels is fitted with a fitting degree better than 0.97. The device has the characteristics of convenient operation, convenient movement, real-time monitoring and low cost. It has a higher precision and practicality than the backscatter lidar in near-ground, which contributes to establish the distribution and movement model of PM2.5 pollutants and make a map of pollution.