The thesis standardized the extension information and the extension knowledge, that is, basing on the information and knowledge, the thesis extended the mutative information and knowledge, and nailed down the conceptions of extension data mining and extension reasoning. This thesis also attested two theorems of the extension data mining and the formula of the extension reasoning. The author put forward the extension data mining which extended from mining the static knowledge to mining the mutative knowledge. So it exploited a new aspect of data mining, and illuminated it by examples.