Cloud liquid water path (i.e. vertically-integrated cloud liquid water) is an important parameter in meteorology and cloud and mist physics. The space-borne microwave radiometer is the most powerful tool for monitoring the distribution and variation of cloud liquid water path on global scale. However, the actual measurements of cloud liquid water path are too limited to carry out the retrieval work. In this study, the manual' data sample is simulated based on a radiative transfer model and a linear regression relationship is obtained between cloud liquid water path and the difference of brightness temperature in cloudy and clear atmospheres from 18.7GHz to 36.5 GHz of AMSR-E. This study is a primary qualitative study to retrieval cloud liquid water path.