Abstract: This study aimed to evaluate the immune effect of a high pathogenic live vaccine of JXAI-R strain on porcine reproductive and respiratory syndrome. Three batches of weaned piglets were immunized with the JXAI-R vaccine and their antibody levels were monitored. The results showed that the antibody effective duration time of the immunized piglets maintained for 11 weeks after receiving single vaccine, and no adverse reaction was observed. It is indicated that the live vaccine of JXAI-R strain is effective for the prevention of porcine reproductive and respiratory syndrome and is safe to use.