Abstract: Langwashan iron deposit is located in the aeromagnetic anomaly zone of Beishan area in Gansu province. Based on the comprehensive study of the regional geological metallogenic background and the characteristics of the magnetic anomaly, it is considered that the iron deposit belongs to the metallogenic island arc volcanic rock, favourable for volcanic iron deposits. The intensive magnetic anomaly areas in the deposit are from the surface or shallow of ore bodies;the wide-and-slow magnetic anomaly is the reflection of the deeply buried magnetic body; the weak magnetic areas in the center of the ring-shaped strong magnetic area, probably influenced by the peripheral strong magnetism, still have good prospecting potential.Langwashan iron deposit is important in Beishan area, hence the results of the magnetic anomalies can guide the exploration of similar deposits.