Objective Methods Experimental mouse were exposed to sodium fluoride ( NaF) added to drinking water，The histopathological changes of testis tissue were observed by HE staining． The apoptosis were detected by TUNEL ( Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling) apoptosis Detection Kit． Results TUNEL-positive cells could be detected in fluoride-treated rat testis．The apoptotic rates of fluoride-treated testis cells were higher than that of control significantly． Conclusions There is tendency of apoptosis in testis of fluorosis in mouse． It is most similitude with change spot of pathology． There may exist apoptosis mechanism in testis lesion of fluorosis．