Objective To observe the changes of intraocular pressure (IOP) following silicone oil tamponade for vitrectomy, and explore the possible causes. Methods The clinical data of 45 patients (45 eyes) undergoing silicone oil tamponade for vitrectomy were retrospectively analysed, and IOP elevation was defined as IOP of 24 mmHg (1 mmHg=0.133 kPa) or higher. Results Postoperative IOP elevation occurred in 22 patients (48.9%), especially in the early period after operation (2 weeks after operation)(17/22, 77.3%). After using IOP-lowering drugs and adjusting or cessation of glucocorticoid eyedrops, the elevated IOP in all patients was controlled within normal limits. There was no significant difference in gender, age, course of disease, refractive diopters and volume of silicone oil tamponade between patients with and without elevated IOP (P>0.05 for all). Conclusion IOP elevation is a common complication following silicone oil tamponade for vitrectomy, and postoperative intraocular tissue edema, uveitis reaction and frequent use of glucocorticoid eyedrops may be the main causes.