The method for recovering lithium hydroxide from a lithium secondary battery allows a powder comprising lithium and valuable metals to be prepared from the lithium secondary battery. The powder is reduced to form a preliminary precursor mixture including a preliminary lithium precursor and valuable metal-containing particles. The preliminary precursor mixture is primarily washed with water (H2O) to generate a lithium precursor aqueous solution and a precipitate. The lithium precursor is recovered through solid-liquid separation of the lithium precursor aqueous solution and the precipitate. The lithium precursor is recovered, through additional washing and solid-liquid separation, from the precipitate obtained through the solid-liquid separation. A calcium compound is added in the primary washing operation or the additional washing operation. Therefore, a highly-pure lithium precursor can be obtained without a complex leaching process and additional processes resulting from a wet process of an acid solution.