The distribution and variation trends of cloud amount and optical thickness over China were analyzed by using the monthly mean data of International Satellite Cloud Climatology Project (ISCCP) D2 from 1983 to 2009. Results show that the total cloud and middle cloud amounts are large in southern China and small in northern China. In Qinghai-Tibet Plateau there are large high cloud amount but smaller low cloud amount. The total and middle cloud amounts increased in eastern China and decreased in western China during the mentioned period, but the low and high cloud amounts decreased in most areas of China. Seasonally, the total cloud amount increased in the north and decreased in the west in spring and autumn, while it increased in most areas in summer and decreased in winter. The cloud optical thickness, which is larger in southern China than in northern China, increased in most areas. Additionally, the differences in the distribution and trends of cloud amount and optical thickness between heavily and less polluted areas were discussed by using Moderate Resolution Imaging Spectroradiometer (MODIS) data from 2001 to 2013. It is shown that the distribution and trends of cloud amount and optical thickness over differently polluted areas of China have different characteristics.