Abstract: Abstract: To verify the application effects of inactivated vaccines of porcine reproductive and respiratory syndrome (PRRS) from different factories and to supply experimental evidence for correct selection of different sources of inactivated PRRS vaccines, the most frequently applied inactivated PRRS vaccines from three factories were compared in adverse reactions and immune effect. It was found that the vaccines used did not cause the adverse reactions such as hypersusceptibility and changes of feed intakes, and that 2 times of vaccinations of the vaccines all effectively enhanced the antibody levels, respectively, in which the No. Ⅲ vaccine stimulated antibody as rapid as the first vaccination was done while the No. I and No. Ⅱvaccines did not result in the antibody by the first vaccination. It was concluded that the No. Ⅲ performed the best immune effect in the used vaccines since it was the most rapid one in producing the antibody and can be taken as the first-selection of inactivated vaccine against PRRS in Zhuhai, Guangdong. Key words: Porcine reproductive and respiratory syndrome, inactivated vaccine, adverse reaction, immune effect, swine