The invention discloses head-mounted and rear-mounted dual-use detachable and adjustable earmuffs. The earmuffs comprise a U-shaped support, a left earmuff and a right earmuff, wherein a U-shaped guide groove is formed in the U-shaped support; an external U-shaped groove is formed in the outer side surface of the U-shaped support; a plurality of tapered guide grooves are formed in two side walls of the external U-shaped groove; the left earmuff and the right earmuff are bilaterally symmetrical in structure; the left earmuff comprises an adjusting and connecting rod, a connecting seat, an earmuff body and an adjusting mechanism, the adjusting mechanism is screwed to the upper part of the adjusting and connecting rod and clamped in the tapered guide grooves, the upper part of the adjusting and connecting rod is inserted into the U-shaped guide groove, the lower part is inserted into the connecting seat, the connecting seat is clamped on the earmuff body through a linear fixing block, and the earmuff body is directional and has front and back. The earmuffs can be head-mounted and rear-mounted, and the components can be detached and separated one by one; the relative distance between the U-shaped support and each of the left earmuff and the right earmuff is adjustable.