The invention discloses a dry powder extinguisher containing modified smectite powder, which is prepared from the following raw materials in parts by weight: 70-90 parts of modified smectite powder, 5-10 parts of mica powder, 10-15 parts of zinc sulfide hydrate, 3-5 parts of calcium hydroxide, 5-8 parts of magnesium stearate, 3-5 parts of nitrogenous silicon oil, 2-3 parts of expandable graphite, 2-3 parts of magnesite, 2-3 parts of urea, 5-8 parts of calcium lignosulphonate, 3-5 parts of bamboo charcoal fiber, 2-3 parts of industrial essence, 2-4 parts of zinc borate, 1-3 parts of chlorinated paraffin and 8-10 parts of kieselguhr. The extinguisher has the advantages of high fire extinguishing efficiency, high moisture resistance, favorable after-combustion resistance, environment friendliness and simple production technique, and is suitable for various fire hazards.