Abstract: On the basis of the researches on crustal deforma tion precursors for years, the complexi ty of the precursors are discussed, and some of theirg enerali ty are fo und through the summari zation of typical crustal deforma tion and st rain precurso rs. Fordescribing the common character, the calculating model of index K of anomaly is given. By means of comprehensive analysis of the K index , backg ro und data and the practical experience, itis possible that prediction fo rsome strong earthquakes withmagni tude more than 6 can be made in sho rttermoreven in imminent stage.

Key words: Deformation, Short-term and imminent precursors, Index