According to the technical key points, the detachable structure comprises a combined collar face, a combined collar face lower lining patch and a combined collar face, one side of the combined collar face is movably connected with one side of the combined collar face, and the side, close to the combined collar face, of the combined collar face is fixedly connected with one side of a down jacket body; the collar cap comprises a collar cap body and a collar combining face, the collar combining face is fixedly connected between the collar combining face and the collar combining face, the collar combining face lower lining is fixedly connected between the collar combining face and the collar combining face, and one side of the collar cap body is movably connected with one side of the collar combining face lower lining. When the device is used, after the collar cap body is detached, the connecting piece used for connecting the collar cap body and the down jacket body can be shielded, and the down jacket is more attractive when a user wears the down jacket without using the collar cap body.