Objective To study the effect of Opuntia on the blood glucose level in rat model of type II diabetes mellitus. Method Rat model of type II diabetes mellitus (DM) was eastablished with streptozotocin (STZ). 60 rats with DM were divided into six groups (10 rats each): normal control (N), DM control (A), PEDG (B), and low dose (E, fed with 3 g/d), moderate dose (D, fed with 6 g/d) and high dose (C, fed with 9 g/d) of Opuntia. Results The blood glucose levels in C (9.21 0.85), D (11.35 0.91) and E(14.40 1.30) groups were significantly decreased in comparison with that before Opuntia administration in groups C and D (P<0.01), and also significant difference compared with group A (P<0.01), but not with group B (P>0.05). Conclusion Opuntia may decrease the blood glucose level in rat model of type II diabetes mellitus, and is worth further studing on its clinical application.