Objective To explore the etiological mechanism of Kashin-Beck disease (KBD) and? the changes of bone on X-ray photography in preschool children in the KBD endemic area. Methods Children of 1-6 years old in Naidang village of Jinchuan county, Sichuan province, China were included; and their wrist and knee joints X-ray photos were collected. The photos were bl indly diagnosed. Results Of the 22 children aged 1-6 years old in the village, 17 were included and another 3 aged 6-8 years old asked for examination. All children showed changes in bone metaphysis around wrist or/and knee joints based on the results of X-ray examination. Conclusion The 20 children in mild type KBD area show common changes in bone metaphysis This result coincides with our hypothesis that hypoplastic cartilage should occur in the population of preschool children in the KBD endemic area.