The large talus landslide of is very complicated and difficult to deal with. In order to make a good research on the influence of rainfalls to the high talus slope deformation, the method of information entropy is employed by using the principle of information transfer and relativity to analyze and calculate the rainfall influence on the deformation velocity. Moreover, taking the full and accurate data of the accumulation body with high slope on the left bank in front of Xiaowan Dam as an example, the information transfer function between rainfall and deformation is established. The actual shows that this new method is convenient, universal and precise. It also demonstrates its great advantage for the analysis of such complex slope deformation problem that has a lot of influencing factors. The method does not make any hypothesis before putting into consideration.