Based on the rich selection of wavelengths and small detection blind zone of LED light source radar, the atmospheric remote sensing lidar system with LED light source can achieve the observation of aerosols at near range and special wavelengths. To reduce the volume of radar system and realize portable observation of atmospheric condition, a compact and easy-to-use atmospheric lidar is designed, which receives echo signals from Fresnel lens. The geometric overlap factor is calculated and analyzed according to coaxial radar transmission and reception principles, and the detection blind zone less than 2 m can be confirmed. The system model is constructed by ZEMAX simulation, and the light intensity distribution and light energy utilization rate of the radar transmission system are obtained. At the same time, by calculating the signal-to-noise ratio, the aerosol detection capability is evaluated and the maximum detection distance is obtained. The simulation results show that three types of LED light source radars which single-pulse energies are 96 nJ, 30 nJ and 105 nJ, wavelengths are 475 nm, 530 nm and 625 nm respectively, can reach the detection distance of 480 m, 200 m and 280 m. It verifies that the compact and easy-to-use LED light source radar system has the ability to detect near-ground atmospheric aerosols.