Abstract: To evaluate the status of the breeding pigs'immunity against classic swine fever virus (CSFV),serum samples from 10 pig farms of different sizes in Fujian were collected and tested with HerdChek CSFV-ELISA kit. The results showed that the average passing rate (i.e.,antibody blocking rate≥50%) of the pigs with sufficient antibody against CSFV on the 10 farms was 88.11%. The average unqualified (i.e.,blocking rate50%) rate was 11.89%,ranging from 5.36% to 28.63%. A booster vaccination with active vaccine was implemented on the breeding swine that failed the test. Four weeks after the vaccination,a similar test was conducted again. It showed the average passing rate had reached 91.44%,i.e.,an increase of 3.33% over the rate prior to the booster vaccination. Based on the results,some preliminary measures for the CSFV eradication program is presented.