Four groups dog tooth enamel samples were irradiated with different dose by ,137,Cs γ-rays. Their electron spin resonance (ESR) spectra pre- and post-irradiated were measured and the changes of ESR signal intensities were analyzed. The results showed that the average intensity of native signals of dog tooth samples was 20.8±2.9, much weaker than that of human 39.5; the dosimetric signal intensities of dog tooth enamel increased with the absorbed doses; the mass of each sample is 100 mg. The average irradiation response of dog tooth enamel samples was (37.1±2.1) Gy,-1, very close to that of human tooth samples (36.3 Gy,-1,). The dog tooth can be used for retrospective dosimetry when human tooth are difficult to collect.