A method for treating aluminum electrolytic waste cathode carbon blocks by an acid and alkali combination method is characterized by comprising the following steps: (1) aluminum electrolytic waste cathode is added to concentrated basic solution for reaction; a filtered solid phase is obtained by filtering and is added to concentrated acid for reaction; and carbon powder is obtained after filtration; (2) filtrates are mixed and dropwise added with the concentrated basic solution, the pH value thereof is adjusted to 9, the obtained mixture is kept standing and filtered to obtain cryolite; (3) the filtrate is added with saturated bleach solution, kept standing and filtered to obtain calcium fluoride; (4) the fourth filtrates is heated, evaporated and crystallized to obtain sodium chloride solid. With the purposes of waste utilization and environmental protection, the method successfully provides the process for treating aluminum electrolytic waste cathode by the acid and alkali method, which causes the waste cathode to not be the conventional waste and pollutant and to become artificial mineral resources. The method solves the problem of waste utilization in aluminum electrolysis industry, improves benefit, and improves the comprehensive level of the aluminum electrolysis industry of China.