Abstract: OBJECTIVE To explore the influence of different influencing factors on the results of pyrogen test for medium/long chain fat emulsion injection, and to improve the accuracy and reliability of pyrogen test results for medium/long chain fat emulsion injection. METHODS The test data of pyrogen test for medium/long chain fat emulsion injection in Suzhou Institute for Drug Control for 5 years were collected and the association between the range of rabbit temperature rise in pyrogen experiment and rabbit weight, sex, basic body temperature, ambient temperature, the number of rabbits used, whether the experimental sample was the same as the previous experiment, and the interval between experiments were analyzed by Apriori association rule. RESULTS "Rabbit temperature rise ≥ 0.4℃" was significantly associated with "basic body temperature 38.0-38.7℃", "ambient temperature fluctuation 1.6-3.0℃", "rabbits were used for 1-3 times", "experimental interval days 2-5 d" and "the same sample was used the previous time". CONCLUSION During the pyrogen test of medium/long chain fat emulsion injection, rabbits with different basic body temperature and use times should be selected as far as possible, and the rabbits using medium/long chain fat emulsion injection in the previous sample should be avoided as far as possible. The experimental interval should be prolonged, and the environmental temperature fluctuation should be maintained to ensure the accuracy and reliability of pyrogen test results for medium/long chain fat emulsion injection.