Abstract: Chamatun iron deposit,discovered by aeromagnetic anomaly screening, high-precision magnetic measurement, magnetic anomaly research and drilling engineering verification, is a medium to large scale concealed sedimentary metamorphic deposit under the Mesozoic volcanic sedimentary rocks. Basing on a detailed analysis of discovery processes and geological characteristics, we proposed the study area was an island-like uplift or a part of Mongolian platform in Proterozoic during the formation and evolution of eastern Hebei to western Liaoning aulacogen. These achievements would provide geological bases for searching sedimentary metamorphic iron ore in western Liaoning volcano-sedimentary basin. Furthermore, the screening methods of ore-induced aeromagnetic anomalies, the approaches and technologies in mineral exploration, and the prospecting direction were discussed. These could provide information and clues for searching concealed iron deposit in similar geological conditions.