Abstract: By using the data provided by CloudSat satellite, the study examines the vertical, geographic, and monthly variations of cloud particle effective radius over China during the summer of 2006-2008. Results show that the liquid cloud droplet effective radius is larger in the low tropospheric atmosphere than that in the middle and upper ones, and it decreases with the altitude. The liquid cloud droplet effective radius is larger in middle latitude zone than that in southern or northern latitude zones. The cloud droplet effective radius is smaller in July and August, while it is larger in June. This feature may be closely related to the Meiyu front systems. The cloud droplet effective radius is larger in the west part and is smaller in the east part of northern and central China, while there is very small difference between the east and west part of southern China. The characteristics of ice particle sizes in the three different latitudinal zones are similar to each other, in which the ice particle effective radii get the maximum value at ice cloud base and decrease with altitude. The inter-annual variation of either liquid or ice cloud particle sizes are not significant. From the features mentioned above, it can be seen the significant influences of plateau topography and East Asian summer monsoon on the vertical and geographic distributions of monthly cloud particle effective radius. The revealed features of monthly cloud particle effective radius can provide baseline information for the further researches on weather and climate models improvement, weather modification and cloud-radiation-climate interaction.