Objective To compare advantage and disadvantage of spontaneous and testosterone-induced benign hyperplasia prostate (BPH) in dogs, and to provide better BPH model for evaluating BPH drugs. Methods 12 male adult beagle dogs were randomly divided into 2 groups, one as normal control group, the other was testosterone (T) group, and 6 old beagle dogs which selected by ultrasound detection was old dog group. After dogs of T group being castrated, all animals except the old dogs were administered 0 and 2.5 mg/(kg.d) by intramuscular injection for 4 weeks. The body weight was monitored every week, the prostate volume was measured by ultrasound detection and blood samples were collected at 24 hours before animal killed after the last treatment. The prostate was removed to measure the wet weight, water content, volume and to calculate the organ coefficient. Then the prostate were fixed in 10% formalin solution, embedded in paraffin, sectioned at 4祄, stained with hematoxylin and eosin. Slides were observed under microscope and analyzed the height of prostatic epithelium(HPE) and acinar luminal area(ALA) with micro-image analysis system(MIVNT). T level, dihydrotestosterone (DHT) level, prostate specific antigen(PSA) level and prostate acid phosphatase(PAP) level in serum and prostate were assayed according to the instruction of magimuzyme kits and ELISA kits. Results ①After 4 weeks treatment, the mean body weight of dogs in three groups were smoothly increased. ②The ultrasound detection results showed that the prostate volume of animals in T group and old dog group were significantly bigger than that of normal control group (P<0.01). ③Based on anatomy results, the real prostate volume of T group and old dog group were significantly bigger than that of control (P<0.05), and the prostate volume of old dog group was bigger than that of T group. Compared with control, the prostate wet weight and organ coefficient of T group and old dog group were significantly increased (P<0.05), and both indexes of old dog group were greater than that of T group. ?According to the data of histopathology, in T group, the hyperplasia prostate showed more gland hyperplasia, especially was prostatic epithelium proliferation, while in old dog group, the hyperplasia prostate mostly contribute to prostatic mesenchyme proliferation. Further MIVNT results showed that, compared with control, the HPE was significantly increased (P<0.01) and the ALA was significantly enlarged in T group (P<0.01), while in old dog group, the HPE was also significantly increased (P<0.01) and the ALA was significantly enlarged (P<0.05), but its HPE was lower than that of T group. ⑤Compared with control, in T group, the T, DHT and PAP levels in serum were slightly increased, and T (P<0.05),DHT (P<0.01), PAP (P<0.05) and PSA levels in prostate were significantly increased; In old dog group, the T, DHT and PAP levels in serum were slightly increased, the T level in prostate was slightly increased, and the DHT, PAP and PSA levels in prostate were slightly decreased. Conclusion Both spontaneous and testosterone-induced BPH model in dogs could be used to evaluate BPH drugs, but there are some differences between these two groups.