The protection effect of vitamin C on ultraviolet radiation-induced DNA damage was discussed. The Raman spectra of the mixture of small amount vitamin C and DNA sdution with ultraviolet radiation of 9 min and 30 min were measured. The intensity of ultraviolet radiation is 18.68 W/m2. When vitamin C (0.2 mmol/L) was add ed to DNA solution, ultraviolet radiation only had a slightly influence on the DNA. Though free radicals generated by ultraviolet radiation in the mixture of DNA solution and vitamin C can cause DNA damage, vitamin C has antioxidative property and it can scavenge free radicals and prevent the reaction between DNA and free radicals. In the other way, both vitamin C and DNA have strong absorbancy at 260 nm ultraviolet. Maybe the vitamin C absorbancy of ultraviolet radiation is stronger than DNA′s, so DNA was protected.