Subconjunctival hemorrhage is one of the commonly encountered problems in ophthalmology. Moreover, subconjunctival hemorrhage is not an independent eye disease, but a feature shared by many eye diseases and systemic diseases, suggesting increased vascular fragility. Specific conditions can be as follows: 1. Diseases of the eye itself: inflammatory infections of the eye, acute conjunctivitis, tuberculous conjunctivitis, conjunctival aneurysms, bleeding due to arteriosclerosis of the fundus, increased intraocular pressure in glaucoma, and other above eye diseases can cause subconjunctival hemorrhage. 2, external injury: violent coughing, vomiting, forceful defecation, trauma, etc. can also lead to subbulbar hemorrhage. 3.Local vascular problems: such as ocular hemangioma, arteriosclerosis or brittleness, and abnormalities of ocular blood vessels can lead to subconjunctival hemorrhage. 4. Systemic vascular problems: vasculitis, hardened and brittle blood vessels, obstruction of venous return in the head, etc. 5. Hematologic diseases: thrombocytopenia, coagulation disorders and other hematologic diseases can also lead to subconjunctival hemorrhage. Subconjunctival hemorrhage can be caused by many factors, generally there is no need to panic too much due to trauma, it can dissipate on its own in a few days, other causes should pay attention to timely consultation, examination to investigate the root cause of the conjunctival hemorrhage, whether it is the eye itself or due to other diseases, treatment for the cause. It is recommended to seek medical attention without delay, as it may be a sign of a serious disease.