In order to identify the prevalence status of three common swine diseases including classical swine fever（CSF），porcine reproductive and respiratory syndrome（PRRS）and porcine pseudorabies（PR）in some regions of China，by the methods of ELISA，PCR and RT-PCR，3 550 swine serum samples delivered by 172 farms in 11 provinces（autonomous regions）in 2019 were tested for the antibodies against CSFV，PRRSV and PRV-gE，and 371 lesion samples from 72 farms in 9 provinces（autonomous regions）were detected for virus antigens. The results showed that the antibody positive rates of CSFV，PRRSV and PRV-gE were 82.75%，84.08% and 31.86% respectively，and the antigen positive rates were 2.62%，26.15% and 1.67% respectively. The average blocking rate of CSFV antibody in nursery pigs was 44.62%，which was the lowest with poor antibody uniformity，and the CV value was 58.26%，CSFV was mainly detected from the lesions of suckling piglets and nursery pigs，with the detection rates of 3.57% and 3.00% respectively. Except for fattening pigs，the mean S/P value of PRRSV antibody was 1.0 to 2.0 for other pigs，with poor antibody uniformity，and the average positive rate of PRRSV antigen was higher（26.15%），in which，the detection rate of PRRSV antigen in nursery pigs was the highest（37.68%）. The positive rates of PRV-gE antibody in fattening pigs，sows and boars were 36.82%，35.31% and 15.65% respectively，and the virus pathogens were mainly detected out in stillborn/mummy fetuses and lesions of suckling piglets，with the positive rates of 8.70% and 2.99% respectively. It was concluded that PRRSV had brought great threat to pig populations at different growth stages in China；the nursery pigs antibody level of CSFV was poor with high risk of outbreak；boars，sows and fattening pigs had been widely infected with PRV，especially sows. Therefore，a series of comprehensive measures including immunization，monitoring and purification and so on should be applied in all farms，so as to strengthen the prevention and control of these common diseases.