The aerosol optical thickness (AOD) in Guangdong Province from 2010 to 2013 was discussed based on the MERSI AOD products of Chinese Polar Orbiting Meteorological Satellite FY3A. It is found that the correlation coefficient between the MERSI AOD products and the groundbased sun photometer measured AOD data is 0.72. The mean absolute error and the root mean square error of the MERSI AOD are 0.12 and 0.15 respectively. So the MERSI AOD data meet the accuracy requirements of the paper. Spatially, a decreasing trend is found in order by Pearl River Delta Region, western region, eastern region and mountainous region. Among them, the mean AOD values are highest in Foshan City, Dongguan City and Zhongshan City, and lowest in Meizhou City and Heyuan City. Temporally, the AOD increases from 2010 to 2011 and then decreases from 2011 to 2013. What’s more, spring has the highest seasonal mean AOD, followed in order by summer, autumn and winter.