Objective: To study comparatively on ultramicro powder of Tianqitongjing capsule and common Tianqitongjing capsule. Method: The dissolution rate of the two kinds of capsules was determined according to relating dissolution rate determination method on China pharmacopoeia. Zero angle of the two kinds of capsules was determined by powder flow ability determinator. The effect of the two kinds of capsules was compared on uterus and ovaries developing of mouse

i.e. the effect of xylene to swelling of ear of mouse and the effect of oxytocin to writhing response of rat. Result: Every target of ultrmicro powder of Tianqitongjing capsule was better than common Tianqitongjing capsule. The ultramicro powder could get to the identical drug action at the dosage of 1/3 comparing with the common Tianqitongjing capsule. Conclusion: The examination laying a foundation for the developing of ultramicro powder technology.