Objective: The aim of our study was to explore the eikonic characteristic of skeletal metastasis of primary pulmonary carcinoma. Methods: Whole-body bone scans with 99Tcm methylene diphosphonate were performed in 258 patients with pathologically proven pulmonary carcinoma. The rate of skeletal metastasis, distribution of the metastatic lesions and their characteristics were analyzed. Results: Among the total 258 patients, 142 cases developed skeletal metastasis. The overall rate of skeletal metastasis was 55.0%. The metastases located in axial skeleton were 49.6%, appendicular skeleton 36.0%, trunk bones of the axial skeleton 48.4%, and appendicular girdle skeleton 31.4%. Ribs, thoracic vertebrae, ilium and lumbar vertebrae had a higher rate of skeletal metastasis, which were 38.4%, 24.0%, 21.7%, 20.2%, respectively. 1252 lesions were detected including 406 at the left side of the body, 387 lesions at the middle position and 459 at the right side of the body. There was no significant difference in terms of number of lesions between left side and right side (X2=3.3, P=0.072). 1224 skeletal metastatic foci (97.8%) were presented as strong radioactive, 26 (2.1%) as mixed lesions, and 2 (0.2%) as low radioactive. According to the shape of lesions, there were 810 punctate lesions (71.5%), 159(14.0%)lump form, 108(9.5%) strip form and 56 (4.9%) lamellar form. The accumulative skeletal metastasis rate was 28.7% for the patients with one to three lesions. The metastasis rate decreased gradually as the number of metastatic lesions increased. Conclusion: Skeletal metastasis is very common in patients with pulmonary carcinoma. Most skeletal metastases are characterized by strong radioactive and earlier punctate form; they often occur in the trunk bones of axial skeleton or appendicular girdles. The distribution of earlier metastases has not obvious regularity, and advanced skeletal metastases are widely and randomly distributed in the body, which are characterized by often concurrently multiple and polymorphous lesions.