Abstract: To study the epidemiology of co-infection of porcine circovirus type 2 (PCV2) , porcine circovirus-like agent P1 (P1) and Torque Teno virus (TTV) in China, 2012, 108tissue and serum samples of diseased pigs obtained from Jiangsu, Anhui and Zhejiang provinces of China were detected for PCV2, P1and TTV by PCR.The results showed that the positive rate of PCV2, P1 and TTV were 12.96%, 33.33% and 51.85% respectively.8samples were positive for both PCV2and P1, 42samples were positive for PCV2and TTV as well, 4 samples were positive for all of the three, and the corresponding co-infection rate were 7.41%, 38.89% and 3.7%respectively.These results indicated that the PCV2 and TTV infection were widespread, while the prevalence of P1infection was lower.The co-infection of different viruses was complicated and the PCV2-TTV co-infection rate was the highest, which increased the difficulty of prevention and controlling diseases of swine.