Abstract: In the mining process of pillarless sublevel caving,the deformation and destruction of blasthole have a strong impact on the blasting effect of mine.It not only bring the problem of big block and hanging arch,but also worsen the ore drawing conditions.Thus it go against the safety production of mine.With the serious destruction of blasthole in the mining process of Dadingshan Mine and the problem of blasting effect and ore dilution loss index can hardly be improved,the main form of deformation and destruction of blasthole such as blasthole plugging,dislocation of blasthole,porhole destruction and diminish of aperture are elaborated based on large number of investigation.Solutions are proposed from the aspects of roadway excavation and supporting way,ground pressure management and control,porthole protection,blasting method and production management.They have acquired good effects in industrial test and they can be significant references in similar mine at present in China.