A DNA molecule is both the carrier of biological information and the main target of biological effects induced by ionizing radiation. Irradiation leads to many types of DNA damage by the direct and the indirect radiation effect. DNA double-strand breaks (DSB) induced by ionizing radiation represent the primary damage of all bio-effects. Currently, the detecting methods dealing with DSB include raman spectroscopy analysis, atomic force microscopy analysis, single cell gel electrophoresis, pulsed-field gel electrophoresis, γ H2AX analysis and premature chromosome condensation analysis, etc. And the statistical models of DNA DSB involve in the random fracture model, the moment method, the tsallis entropy model and the average molecular weight method. Both of them have been discussed in this paper. Finally, the research prospect of the DNA DSB radiation hotspot is presented.