Abstract: Rabbits without Classical Swine Fever (CSF) antibody were employed to produce Classical Swine Fever Vaccine (CSFV) to study the effect of hot summer weather on rabbit body temperature and the rate of regular type CSF in rabbits injected with CSFV thick liquid of spleens and lymph nodes.The results showed that all rabbit body temperature was over 41℃ and 40℃ when the surrounding temperature was up to 38℃ and 35.5℃,respectively.In varying degrees these rabbits showed heliosis symptom.After raised at 22℃ in a GMP animal house for 3 days,they were divided into 5 groups to be injected with 4000 fever units of the CSFV.The rates of regular type CSF in the 5 groups of the inoculated rabbits were 47%,65%,73%,54% and 63%.The rates for the control groups were 96% and 98%.The rabbits in the control groups had no CSF antibody and were raised in the surrounding temperature of 17-25℃.They were injected with the same dosage of the CSFV after being transported to the environment at 22℃.The above result revealed that an optimum surrounding temperature was necessary when the rabbits were to be used for CSFV production.In addition,the subject rabbits should avoid heliosis during the late production process and transportation.However,rabbits with heliosis could still be used to produce CSFV from their spleens and lymph nodes if they had contracted the regular type CSF.