Provided is a focusing assembly including a focusing barrel and a barrel retaining ring; the focusing barrel includes a first sleeve, a second sleeve, and a third sleeve that are sequentially sleeved from inside to outside of the focusing barrel; the first sleeve is provided with a lens mounting portion for mounting a focusing lens, a first end of the second sleeve is provided with a display screen mounting portion for mounting a display screen, a second end of the second sleeve is detachably connected to the barrel retaining ring, the first end and the second end being opposite ends of the second sleeve; and the lens mounting portion and the display screen mounting portion are configured such that the relative position thereof in a focusing direction of the focusing assembly is adjustable.