OBJECTIVE To present a new technique for orbital decompression that minimizes surgical approaches while maximizing the removed areas of orbital walls and to evaluate the efficacy and safety of it for patients with severe thyroid associated ophthalmopathy (TAO). METHODS A retrospective review of 40 cases (66 eyes) with severe TAO undergoing the modified decompression between January 2009 and January 2011 was conducted. All patients were assigned to three groups, which were group CON: compressive optic neuropathy in 30 eyes, group MP: marked proptosis in 30 eyes, and group EK: exposure keratopathy in 6 eyes. The deep lateral, medial walls and orbital floor decompressions were underwent via an eyelid crease or a lateral sub-brow S-shape approach with a transcaruncular approach. Clinical outcomes were recorded including visual acuity, exophthalmometry, diplopia, clinical activity score (CAS) and CT scans before and 6 months after surgery. Intra- and postoperative complications were recorded. RESULTS The postoperative visual acuity was improved in 17 eyes (56.7%, P < 0.05) of group CON. The mean proptosis reduction was (8.1 ± 2.7) mm (t = 11.73, P < 0.01) and (11.4 ± 3.1) mm (t = 15.52, P < 0.01) in group CON and group MP, respectively. The CAS was decreased in group CON (P < 0.01). Compared with preoperative records, the degree of diplopia was not significantly different in group CON (U = 131.0, P = 0.309) and group MP (U = 157.5, P = 0.881). Diplopia resolved in 7 cases (39%) of group CON, 5 cases (28%) of group MP. New-onset diplopia or its aggravation was recorded in 3 cases (17%) of group CON, 4 cases (22%) of group MP. The other postoperative improvement included recovered color vision, reduced intraocular pressure, and healing keratopathy. The important complications were intraoperative dural tears, new-onset diplopia and ocular inferior displacement. CONCLUSIONS The modified orbital decompression offers wide exposure to the three orbital walls, marked proptosis reduction, and no apparent scar. It is efficacious and safety for the treatment of CON and inflammatory activity of TAO without serious complications, meanwhile, has little risk of induced diplopia.