The spectra distribution of solid deoxyribonucleic acid(DNA) at the fore2and aft induced by ultraviolet ra2 diation are obtained by grating2spectrograph. The results show :884cm- 1 ,1010cm- 1 ,1068cm- 1which belong to de2 oxyribose2phosphate and c2o stretch show variour degrees of decrease 1468cm- 1 belonging to deoxyribose disappears ; in the marker band of some base , thymine at 652cm- 1 disappears ; thymine at 670cm- 1 appears ; ademine at 1304cm- 1 increases ; guanine and sytosine at 1526cm- 1 decrease.