AIM: To evaluate the ophthalmic manifestations, radiographic features, and prognosis of Chinese patients with primary orbital mesenchymal chondrosarcoma (MCS). METHODS: The study included 6 cases with primary orbital MCS treated at Tianjin Eye Hospital from January 2009 to December 2019. Patitent ophthalmic manifestations, radiographic features, diagnosis, pathology, therapeutic regimens, and prognosis were retrospectively reviewed. RESULTS: Six patitents with primary orbital MCS were identified. The mean age at the first visit was 33y (range, 25-42y). All six patients displayed manifestations of exophthalmos, diplopia, limitation of eye displacement, upper eyelid oedema, decreased visual acuity and ptosis. The mean disease history and range were 5 and 2-8mo, respectively. The tumors were located in the superonasal extraconal compartment (2/6, 33.3%), intraconal compartment (2/6, 33.3%), and bitemporal extraconal compartment (2/6, 33.3%), respectively. Radiographic features were a well-defined, orbital mass with calcification and ossification on computed tomography (CT), and marked heterogenous enhancement on dynamic magnetic resonance imaging (MRI). Five patients were treated with tumor resection and one patient received orbital exenteration. Five patients in the cohort received postoperative radiation therapy, two patients received chemotherapy, and one patient did not receive postoperative adjuvant therapy because he refused. The histopathologic classification revealed a tumour composed of a mixture of mature chondroid tissue surrounded by small, round, and undifferentiated mesenchymal cells. Immunohistochemistry revealed Bcl-2, vimetin, CD99, and S-100 were expressed were expressed. After surgeries, two patients have developed a local recurrence. The median recurrence time of 58mo (52-64mo). One patient had distant recurrence included the lungs occurred 52mo after the initial surgery. CONCLUSION: The possibilty of orbital MCS need to be considered when a painless, slowly growing orbital mass with calcification and ossification. From our experience, trimodality treatment of radiation therapy, chemotherapy and surgery maybe the best option. Orbital MCS has a high tendency for late recurrence, regular long-term follow-up after complete excision is mandatory.