Objective To analyze the CT, MRI imaging manifestation and pathological features of patients with primary tumor of dacrycyst. Methods The clinical data of 12 patients with primary tumor of dacrycyst diagnosed in the hospital from February 2008 to August 1818 were retrospectively analyzed. All patients were given CT, MRI imaging and pathological examination. CT, MRI imaging manifestation and pathological features of 12 patients with tumor of dacrycyst were analyzed. Results (1) CT: There were 8 cases of regular tumor morphology, 3 cases of nasolacrimal duct spreading, 3 cases of fusiform soft tissue density lump in the lacrimal sac area, uneven density and unclear boundary with surrounding structure, it would invade the nasolacrimal duct, wall bone was destroyed, lumen expanded, there was inhomogeneous moderate enhancement after enhanced CT scan. There were 2 cases of lacrimal sac mixed tumor, CT imaging manifested elliptical soft tissue density lump in the lacrimal sac area, uneven density and edge smoothness. (2) MRI: There were 7 cases of regular tumor morphology, 8 cases of nasolacrimal duct spreading. Taking cerebral cortex signal as reference, there were 6 cases of equal T1, equal T2 signal by MRI imaging, 3 cases of equal T1 and slightly short T2 signal, 1 case of slightly shorter T1, equal T2 signal, 2 cases of mixed T1, short T2 signal. There were 6 cases of T2WI combined with cystic change noted by MRI scan, 1 case of cystic change and bleeding phenomenon, 10 patients with malignant tumors on the DWI, the mean ADC value was (0.90±0.16)×10-3mm2 /s. (3) Pathological results: There were 10 malignant tumors in 12 patients, including 4 cases of squamous cell carcinoma, 3 cases of transitional cell carcinoma, 2 cases of melanoma, 1 case of borderline tumor and 2 cases of benign tumors, all of them were inverting papilloma. Conclusion Patients with primary tumor of dacrycyst have typical CT, MRI imaging manifestation and pathological features. The combined examination of the three methods can demonstrated the location, morphology and benign and malignant aspects of primary tumor of dacrycyst clearly.