Abstract: Using neutrons of 14 MeV generated by 600 kV CockcroftWalton accelerator, the DNA samples with or without mannitol or VND3207 were irradiated with various absorbed doses, and the DNA strand breaks were determined by means of gel electrophoresis. The results indicate that neutron can produce the DNA single and doublestrand breaks, and the yields of strand breaks increase with the dose increment, i.e. there is a distinct dose response. Although for the solution system with additive of mannitol or VND3207, there is also a dose response, the yields of DNA strand breaks are much less than that without mannitol or VND3207 solution. It can be suggested that mannitol or VND3207 reduces the yields of DNA single and doublestrand breaks induced by neutron irradiation efficiently, and mannitol or VND3207 has stronger capability of radioprotection against neutron radiation.