Shepherd's purse extract and preparation method and application thereof

The invention belongs to the technical field of medicines, relates to a shepherd's purse extract as well as a preparation method and application thereof, and further relates to preparation of temperature-sensitive ophthalmic gel of the shepherd's purse extract and application of the ophthalmic gel in preparation of drugs for treating cataract and xerophthalmia. The shepherd's purse extract is prepared by the following method: subjecting shepherd's purse to crushing, extracting or enzymolysis to obtain extractum with the total flavone content of 6% or above, dissolving the extractum with water,and perenriching with D101, AB-8 or AB-8-D101 tandem type macroporous resin to obtain the shepherd's purse extract with the total flavone content of 50% or above. The extract has good effects of treating cataract and xerophthalmia and relieving eye fatigue, the temperature-sensitive ophthalmic gel prepared from the extract is subjected to phase transformation at the temperature of 32.5 DEG C, andthe retention time in the