AIM: To explore the role of positron emission tomography-computed tomography (PET-CT) examination in the diagnosis and treatment of ocular adnexal mucosa associated lymphoid tissue lymphoma (OAML). METHODS: The general clinical data, postoperative PET-CT results, treatment regimens, and the prognosis of 21 histopathologically confirmed OAML patients between October 2017 and September 2021 were collected. Among the 21 patients, five patients underwent surgical treatment alone, 13 patients underwent surgical treatment combined with radiotherapy, and three patients underwent surgical treatment combined with chemotherapy. RESULTS: The follow-up period ranged from 8 to 79mo, with four cases of recurrence and no deaths. Through PET-CT examination, two patients exhibited both local ocular metabolic elevation and systemic metastasis, and one of these patients had cervical lymph node metastasis, while the other had submandibular and parotid gland metastasis. Nine patients showed only local ocular metabolic elevation, while 10 patients had no abnormal metabolic activity locally. CONCLUSION: PET-CT examination plays a crucial role in detecting residual lesions and recurrence following tumor resection, aiding in precise disease staging, and facilitating the development of personalized treatment plans, ultimately improving patient prognosis.