From March to November 2019,the largest on-station comparison observa tion calibration (OCOC) in China was carried out so far,based on the mobile REAL sta ndard aerosol lidar certified by the European lidar calibration center.In this paper, a method for OCOC is firstly introduced.Then,the first OCOC between REAL lidar and 12aeros ol lidars distributed in Beijing,Shanghai and Guangzhou were carried out separately at 532nm wavelength.The 11radars which were calibrated in advance ac cording to method of hardware and software calibration established by the meteorological ob servation center (MOC) were quantitatively evaluated according to the preset quality crit eria,and the results show that the 11radars basically meet the requirements.The system devi ation (SD) of 9radars P/S channels within a range of 2—5km was all in ±20%,and the SD of m ore than 50% of the calibrated radars P channels within a range of 0.5—2km is basically in ±10%.The main problems are P/S channel crosstalk and detector saturation,etc.This work deter mines the reliable range of data of calibrated radars and provides support for operational quantitative application of aerosol lidar.