Abstract: Objective To evaluate the correlation between primary acquired nasolacrimal duct obstruction (PANDO) and anatomy of bony nasolacrimal duct (BNLD). Methods Thirty-one cases (62 eyes) of PANDO patients admitted to our center from March 2019 to January 2020 were selected into the case group with an average age of (57.84±14.05) years.There were 6 males (12 eyes) and 25 females (50 eyes).Another 11 patients (22 eyes) without lacrimal duct obstruction were selected in the control group,with an average age of (56.54±12.26) years,including 2 males (4 eyes) and 9 females (18 eyes).Both two groups underwent maxillofacial cone beam CT (CBCT) scanning.The BNLD parameters,including the anteroposterior diameter (APD) and transverse diameter (TD) at different planes,length,and angle between the inferior turbinate and upper part of the medial wall of the maxillary sinus,were measured in the two groups.Volume of nasolacrimal ducts was calculated using the software of GE Advantage Workstation and was compared between the two groups. Results The entrance APD (6.22±0.74mm vs5.52±0.81mm,P=0.012),distal end APD (8.18±1.39mm vs7.15±1.06mm,P=0.031) and distal end TD (6.14±0.82mm vs5.39±0.87mm,P=0.014) in the case group were significantly greater than those in the control group (P<0.05,respectively).There was no statistical difference in the BNLD parameters between male and female patients in the case group (all P>0.05);and there was no statistical difference in these parameters between the healthy side and the diseased side in the case group (all P>0.05). Conclusion The anatomy of the nasolacrimal duct has no correlation with the occurrence of PANDO,and it shows no gender difference.However,the number of enrolled male patients is relatively small,which needs further verification by the large sample size study;the widening of the orifice may be a secondary change of nasolacrimal duct obstruction.More researches are needed on the exact cause of PANDO.