Antibiotics have been widely detected in livestock waste. The removal of antibiotics from livestock waste before they are exposed to the environment is crucial. Anaerobic digestion (AD) is an effective technique to deal with livestock waste. However, tetracycline was found to inhibit the AD process. In this research, effects of CaO2 addition on the tetracycline removal and methane production during the co-digestion of corn straw and chicken manure were investigated. Results showed the presence of tetracycline in AD system reduced methane yield by 8.8%. Addition of CaO2 at the dose of 0.032 g/g TVS (total volatile solid of substrate and inoculum) improved methane yield by 4.8% and shortened lag-phase by more than 2 days. Using CaO2 also accelerated the removal of tetracycline, therefore mitigated its inhibition effect. The microbial communities of the co-digestion system were also affected by tetracycline/CaO2 addition. The addition of tetracycline especially CaO2 led to increased relative abundance of microorganisms associated with complex substrate degradation. This study indicated that using CaO2 is a promising way to accelerate tetracycline removal and improve methane production during AD of antibiotic-containing organic wastes.