Abstract: Deep seam floor mining damage indexes are controlled by mining floor stress field,distributed fracture in floor rock and applied coal mining method.Deep seam floor mining damage index controlling index system and each controlling index's couple in the damage process are given and analyzed. The comprehensive principal-component analysis model is set up and thirteen main controlling indexes of deep seam mining damage index are selected out.This method can convert the qualitative question to the quantitative,which can more objectively and corrcetly analyze and research this kind of question.