The invention provides a manufacture method of a particle potash fertilizer. A potash fertilizer qualified finished product with a particle size of 2-5.6mm is prepared by tabletting, drying, fragmentation, granulation and screening, with powdered potash fertilizer produced by a water-salt method as the raw material. The raw material powdered potash fertilizer has a water content less than 4.0%. A pressure roller gap of a tablet machine needs to be adjusted to control a tabletting thickness during tabletting and granulation; a depth of a roller skin pattern groove of a pressure roller is 5-8mm; a long shaft is 45-50mm; a short shaft is 35-45mm; and a pressure of a pressure roller wire is no less than 5KN/cm. A turn-over type of dryer is employed for drying with a temperature controlled lower than 220 DEG C and a water content lower than 1.5%. A roller gap of a crusher is adjusted to 3-8mm during fragmentation. After granulation, particles need to be graded; particles with a particle size less than 2mm are recovered to the tabletting step for further treatment, and particles with a particle size larger than 5.6mm are recovered to the fragmentation step for further treatment until having a qualified particle size. During screening, a first screen has a mesh count of 3-5 mesh, and a second screen has a mesh count of 17-19 mesh. Fragmented particles are granulated by a granulator to have smooth edges, so as to reduce powder generated during transportation.