Based on the MODIS cloud products data (MYD06) in Beijing region from January 2007 to December 2008, the probability distribution and seasonal variation characteristics of cirrus optical thickness, effective size and cirrus top height were analyzed. Cirrus probability of occurrence was also studied. The results show that the distribution of cirrus top height is mostly from 6 km to 12 km, the typical cirrus top height is about 9 km. The distribution of cirrus top height varies with seasons. The distribution of cirrus effective size is from 20 μm to 80 μm mostly, and the most probable cirrus effective size is from 40 μm to 50 μm. The relation between cirrus effective size and seasons is not very obvious, but cirrus effective size is definitely dependent on cirrus top height. The ice clouds in Beijing region are mostly opaque. The distribution of cirrus optical thickness is mostly from 0 to 10, and the probability of cirrus optical thickness is bigger when cirrus optical thickness is less than 5. The probability of occurrence and optical thickness of cirrus in winter is small.