Objective To explore the therapeutic effect of Hypericum japonicum on the hyperuricemia rat model. Methods Seventy-two SD rats were randomly divided into six groups: a blank group, model group, low, medium, and high dose groups of Hypericum japonicum, and a Febrista group. Except in the blank group, the hyperuricemia model was established by intraperitoneal injection of 250 mg/ (kg·d) potassium oxonate. The blank group was administered the same volume of normal saline as the control. After 4 weeks of continuous modeling, the Febrista group was treated at 0. 01 g/ (kg·d) administered by gavage, and the low, middle and high dose groups of Hypericum japonicum were treated at 0. 16, 0. 22, and 0. 27 g/ (kg·d) by gavage, respectively. Changes in general living conditions and the appearance of rats, serum biochemical indicators (UA, BUN, Cre, ALT, and AST) and serum proinflammatory factors (TNF-α, IL-17, and IL-18) were observed and compared. Changes in the renal pathology of rats were also observed and compared. Results Each dose of Hypericum japonicum improve a series of symptoms, such as a poor mental state and slow movement of rats. Hypericum japonicum also significantly reduced the serum levels of uric acid, creatinine, and urea nitrogen in the model group, and the improvement was dependent on dose. IL-17, IL-18 and TGF-α levels in medium and high dose groups of Hypericum japonicum were decreased significantly. Pathological observations also showed that Hypericum japonicum improved atrophy of the glomerulus and swelling of the renal tubular lumen, and renal interstitial fibrosis was significantly improved with only a small number of infiltrating inflammatory cells. The improvement of the renal status was dependent on dose. Conclusions Hypericum japonicum reduces blood uric acid and may elicit protective and therapeutic effects in the kidney of hyperuricemia model rats by inhibiting inflammatory reactions.