The inner mechanisms were put forward solely by the author Yang Bingru. Among the inner mechanisms the double-base cooperating mechanism, double-basis fusion mechanism and information increasing mechanism are introduced in this paper. The expansibility structural models of KD (Knowledge discovery) are described including KDD*, KDK*, KD (D&K) and DFSSM, etc.. Some innovative methods, such as a mining algorithm and auto-evaluation method are introduced. On the basis of all above parts, KDTIM (Knowledge discovery theory based on inner mechanism) theory is the advanced theory, and explaination of the mainstream driving to KD brought byresearch on inner mechanism and KDTIM is presented.