The invention discloses a fire extinguisher valve body and a high-finished-product-rate preparation method thereof, and belongs to the technical field of fire extinguisher valve body preparation. The method comprises the steps that a zinc alloy bar is firstly prepared, a salt spray test is implemented to the obtained zinc alloy bar, and corrosion resistance evaluation is given; then the zinc alloy bar is cut into small sections to be put in heating equipment to be heated and subjected to heat preservation; stamping equipment is started to carry out stamping forming on a zinc alloy bar blank, after the valve body is machined, a machined mounting hole is subjected to burr removal, an internal thread of the valve body is subjected to re-threading to remove thread burrs, and an inner hole of the valve body is subjected to ultrafine extrusion to improve roughness; and the obtained valve body is ultrasonically cleaned, and the finished fire extinguisher valve body is prepared. Compared with a copper valve body, the prepared zinc alloy fire extinguisher valve body is low in cost, and a fire extinguishing agent can be prevented from being corroded well; and compared with an aluminum alloy valve body, surface anodic polarization treatment is not needed, water washing does not need to be constantly carried out in the machining process, and the machining speed and the finished product rate are increased to a large degree.