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The antioxidant activities of the soluble eggshell membrane protein (SEP) and its peptides were investigated by using a chemiluminescence (CL) method in vitro. The scavenging ability of SEP and its peptides on superoxide anion, hydroxide radical, and hydrogen peroxide was determined by the pyrogallol-luminol system, the FeSO4-Luminol-H2O2 system, and the luminol- H2O2 system, respectively. DNA damage preventing the effect of SEP and its peptides was determined by the CuSO4-Phen-Vc- H2O2-DNA CL system. The results showed that by addition of sample, the peak CL was reduced, and the integral area of the curve was also decreased, which showed SEP and its peptides can availably scavenge superoxide anion. Trypsin hydrolysate (TH) led to an almost complete inhibition (92.54％) at the 0.5 mg/mL concentration, and the half-inhibition concentration (IC50) of TH was 0.270 mg/mL. As in the case of FeSO4-Luminol-H2O2 CL, all the samples tested were effective in scavenging hydroxide radical. The alkaline proteinase hydrolysate (AH) of SEP could scavenge hydroxide radical most effectively of the samples (the IC50 value was 0.266 mg/mL). The AH had the best scavenging ability on hydrogen peroxide as well, which had the lowest IC50 value (0.384 mg/mL). The pepsin hydrolysate (PH) was the most powerful on the DNA damage preventing effect in all of the samples (the IC50 value was 0.353 mg/mL), and its protection mechanism of samples on damaged DNA belonged to the mixed type, which showed both inhibiting and delaying activities. These results suggested that SEP and its peptides were the potent antioxidant.