OBJECTIVE To study the effect of changes of intraocular pressure on the ocular blood flow.METHODS We established the acute high intraocular pressure model(IOP)by the perfusion of anterior chamber,making the IOP as 40 mmHg(1 mmHg=0.133 kPa).Microspheres technique was used to measure the blood flow of iris,sclera and choroid when IOP was normal and high at the time of 30 min,60 min,90 min and 150 min.RESULTS With the high IOP,the blood flow of iris was normal,while the blood flow of sclera and choroid were declined significantly(P0.05),which were changed with the time prolonging(P0.05).CONCLUSIONS High intraocular pressure has the effect on the blood flow of sclera and choroid,different tissue has different reaction on the high IOP.