The study of FY2C time series imageries shows that the hour range of the pixel's brightness temperature(BT)/temperature(the difference of brightness temperature/temperature within one hour, also called as the hourly change of BT/temperature) in time series cloud imageries can be utilized in the cloud detection of nominal imageries, and in identifying clouds that are developing rapidly or located at the boundaries of the moving clouds. Using the data from Chinese ground stations as a standard, the comparative study is carried out. The combined use of time series imageries and the clear background method in cloud detection brings the accuracy of 72.89% and 79.94% in January and June 2007 respectively. Compared with the current operational cloud detection, the detection of low clouds and thin clouds is improved to a certain degree by the use of the high time resolution of stationary satellites. Using the high time resolution of stationary satellites, a new idea for dynamically obtaining thresholds is provided, and can be put into application in further.