The invention provides a soft iron-brass composite band structure and a welding method thereof. The soft iron-brass composite band structure uses two materials of soft iron and brass to overlay on the surface of an elastic body; the soft iron is located at the back of a band; and a brass part is located at the front part of the band. The welding method comprises the following steps of: firstly, welding a soft iron part; overlaying the brass part after cutting and machining to be flat; and finally, secondarily machining to form the entire band meeting design requirements. According to the soft iron-brass composite band structure and the welding method thereof provided by the invention, the properties and functions of the band can be improved by using own characteristics of the brass and the soft iron to complement the advantages of the brass and the soft iron. The characteristic of good air closeness of a soft iron band is maintained by using the composite band, so as to achieve a wider cannonball firing range. Compared with a brass band, the composite band only has the advantage that a half amount of the brass is used, so that the manufacturing cost is lowered. The composite band has the advantage of larger flexibility. Compared with the brass band, the soft iron band has the advantages of high strength, high rigidity and better air closeness. The rigidity, air closeness and the like of the band can be adjusted by adjusting the ratio of the soft iron and the brass in the band.