Objective To evaluate the diagnosis of frozen shoulder with the coracohumeral ligament on the coronal oblique plane with MRI.Methods There were 60 patients(120 shoulder joints)in control group,with 30 males and 30 females,the mean age was 50.5 years old.There were 72 shoulder joints in 72 patients of frozen shoulder group(50 femles and 22 males with a mean age of 53.5 years)with clini-cal evidence and MR imaging evidence of frozen shoulder.These were prospectively analyzed to identify the CHL visualization rate and meas-ure the maximum thickness of the CHL.Results The CHL visualization rate on the coronal oblique plane in the control group was 86.7%(104 /120),and the frozen shoulder group was 87.5%(63 /72),the difference was not significant(P >0.05).The CHL visualization rate on the axial view in the frozen shoulder group was 19.4%(14 /72)and the control group was 24.2%(29 /120),the difference was not signifi-cant(P >0.05).The CHL thickness on the coronal oblique plane (n =63)in the patients with frozen shoulder was (4.37 ±1.71)mm, which was significantly greater than (2.84 ±0.79)mm ofpatients in the control group(n =104),the difference was significant(P <0.001). The CHL thickness on the axial plane(n =14)in the patients with frozen shoulder was (3.93 ±1.49)mm,which was significantly greater than (2.29 ±0.65)mm of patients in the control group(n =29),the difference was significant(P <0.001).Conclusion A thickened CHL is highly suggestive of frozen shoulder,which is 4.37 mm on the coronal oblique plane.