Abstract: This paper mainly studied the effect of Xiyanping injection on the bacterial endotoxin lipopolysaccharide (LPS)-induced fever in rabbits, preliminarily investigated the mechanisms, and provided pharmacological basis for the clinical application. The rabbit model of endotoxin-induced fever was established by using LPS as the inducer; The changes of rectal temperature were measured; The levels of prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and phospholipaseA2 (PLA2) in the serum were measured; The levels of PGE2, cyclic adenosine monophosphate (cAMP), and arginine vasopressin (AVP) in cerebrospinal fluid as well as hypothalamus were detected. The animal welfare and experimental process are in accordance with the regulations of the Animal Ethics Committee of China Pharmaceutical University in this study. The results showed that Xiyanping injection (12.5, 25, and 50 mg·kg^-1) could significantly reduce LPS-upregulated body temperature of rabbits, and the duration of action could reach 5.5-8.5 h. At the doses of 25 and 50 mg·kg^-1, the antipyretic effect of Xiyanping injection was comparable to that of analgin injection (50 mg·kg^-1). Furthermore, Xiyanping injection and analgin injection both reduced the levels of PGE2, IL-1β, TNF-α, and PLA2 in the serum of febrile rabbits to the varying degrees. In addition, Xiyanping injection also down-regulated the levels of PGE2, cAMP, and AVP in the hypothalamus, and PGE2 and cAMP in the cerebrospinal fluid. The level of AVP in the cerebrospinal fluid was up-regulated. This study indicated that Xiyanping injection could significantly improve the endotoxin-induced fever in rabbits, and mechanisms were closely related to the regulation of the levels of PGE2, TNF-α, IL-1β, PLA2, cAMP, and AVP in serum, hypothalamus, and cerebrospinal fluid.