Objective:To compare the value of cone-beam CT(CBCT)and spiral CT(SCT)in the diagnosis of tem-poromandibular joint disorders(TMJD).Methods:A total of 84 patients(168 joints)with suspected TMJD were selected as the research subjects.All patients underwent CBCT and SCT examinations.The width of the anterior,superior and posterior space of bilateral temporomandibular joints was measured,and the detection rates of condylar bone erosion,osteosclerosis,cystic de-generation,articular fossa flattening and osteophyte formation were evaluated.The clinical comprehensive diagnosis(symptoms+joint X-ray+MRI)was used as the gold standard,and the diagnostic efficacy indicators such as sensitivity and specificity were calculated.Results:There was no significant difference in the measured values of the left and right joint space between CBCT and SCT(P>0.05).The detection rate of bone erosion,cystic degeneration and osteophytes by CBCT was higher than that by SCT(P<0.05).Based on the gold standard,75 cases of TMJD were finally diagnosed in 84 cases,73 cases of TMJD were detected by CBCT,and 68 cases of TMJD were detected by SCT.The positive detection rate of TMJD by CBCT was higher than that by SCT(P<0.05).The sensitivity and accuracy of CBCT in the diagnosis of TMJD were better than those of SCT(P<0.05).Conclusion:CBCT and SCT have good consistency in the measurement of bilateral temporomandibular joint space,but CBCT significantly improves the detection ability of early bone lesions in TMJD and has higher diagnostic accuracy.