Abstract: Disclosed in the present invention is a high-precision externally-adjustable coffee grinder, including a main housing, a lifting rod, a grinding assembly and a coarseness adjusting structure, where the coarseness adjusting structure includes an external adjusting ring, an internal driving ring, a transmission gear; the external adjusting ring is sleeved and rotates relative to the main housing; the external adjusting ring is engaged with the internal driving ring through the transmission gear; and the external adjusting ring drives the internal driving ring to rotate to drive the lifting rod to adjust a grinding disc gap. The adjusting precision of the adjusting structure is greatly improved, the advantages of convenient adjustment of the externally-adjustable coffee grinder and clear scale indication of a one-turn coffee grinder are retained, and the problem of low precision of the one-turn adjusting coffee grinder in the prior art is solved.