26 cases with Temporomandibular Joint Dysfunction Syndrome (TMJDS) were included in the present study. Fully corrected lateral tomogrames of TMJ in the intercuspid position were taken for all the cases; and fully corrected lateral arthrotomogrames were taken for 19 cases (21 joints) of them. The area and linear measurements of the joint space were made with the aid of computer. The results showed that the position of the condyle in the patients with TMJDS was located in the posterior position of the fossa. Statistics results showed that there was significant difference between the patient group and control group. Although the posterior displacement of the condyle was often associated with the anterior displacement of the disc, it was not always agreement with the anterior disc displacement. So, the exact diagnosis of disc displacement should be still on the basis of arthrography or other examinations, such as CT or MRI.