The invention discloses a method for extracting and separating valuable metal from secondary lead smelting slag. The method includes the steps that a certain amount of oxidizing agent is mixed in the secondary lead smelting slag to be treated; after a certain amount of NaOH solution is added, leaching treatment is conducted in a stirring mill; pulp obtained through leaching treatment is subjected to solid-liquid separation, and filter residues rich in lead and antimony and filtrate rich in tin and arsenic are obtained after washing; the obtained filtrate rich in tin and arsenic is subjected to impurity purifying treatment, and a sodium stannate solution is obtained; and the obtained sodium stannate solution is condensed and crystallized to obtain a sodium stannate product. The method is simple in process and easy to adopt, valuable metal such as tin, antimony and arsenic can be directly separated under the alkaline condition, a qualified sodium stannate product is obtained through subsequent purifying and impurity removing, and the recycling rate of the valuable metal is increased.