The purpose of the experimental study is to observe the effect of the immune recall responses induced by intramuscular (i.m.) injection with concentrated Primary Hamster Kidney Cell Vaccine(PHKCV) on days 180, 365, 545 and 730 after 0.1 mL nonconcentrated PHKCV was inoculated intradermally (i.d.), so as to determine the duration of the immunologic memory induced by i.d. 0.1 mL nonconcentrated PHKCV and chieve the goal of protecting the rabies patients with a short incubation. The results indicated that there were four intervals of 180, 365, 545 and 730 days between i.d. and i.d. PHKCV, the seroconversion rates being respectively 96.55%, 100%, 100%(180 day); 76.67%, 100%, 100%(365 day); 75.86%, 100%, 100%(545 day) and 75.00%, 100%, 100%(730 day) on days 7, 14 and 30 after the first dose i.m., the seroconversion rates of four experimental groups were all markedly higher than that of five routine doses (40.74%) (P < 0.01) on days 7 after the first dose i.m. The immune endurance of concentrated PHKCV and the enhancing immune effect of the vaccine following booster injection 365 days later were also observed. The results indicated that the seroconversion rates on days 180, 365 and 380 (on day 15 after boosting injection) were 96%, 83.33% and 100% respectively. The stated results prove that the concentrated PHKCV has better immune endurance and the immunologic memory induced by i.d. 0.1 mL nonconcentrated PHKCV can maintain two years. The immune effect inoculated by i.m. two or three doses on day 730 after i.d. 0.1 mL nonconcentrated PHKCV was better than that of five routine doses as the first time vaccination. If intradermal micro-injection were performed with higher titre of rabies vaccines, the longer time of immunologic memory would be maintained.