The invention discloses a method for recovering valuable metal from waste ternary lithium-ion battery powder. Firstly, the waste ternary lithium-ion battery powder is put into a pit furnace into whichoxygen is fed to be subjected to oxidizing roasting, a roasted product is obtained, the content of carbon in the roasted product is reduced by 99% or above, then, the roasted product is dissolved inan ammonia-ammonium chloride solution system to be put into a reaction still, hydrazine hydrate with the volume fraction being 1.6% is added to serve as a reducing agent, a pH value of an obtained lixivium is adjusted to be 8.00, according to the ratio of O / A being 2, the lixivium is added into an extraction agent, the volume fraction of Versatic 911 is 20%, the volume fraction of sulfonated kerosene is 80%, the reaction temperature is controlled to be 30 DEG C, 5 minutes later after the reaction, raffinate and an organic phase are obtained through separation, and through 3 levels of counter-current extraction, the extraction rate of cobalt is 98% or above. According to the method, adopted equipment is simple, the investment running cost is low, the process energy consumption is remarkablyreduced, and the recovery rate of the valuable metal is high.