The invention discloses a method for composite production of high-purity lithium hydroxide monohydrate, high-purity lithium carbonate and battery grade lithium carbonate. Industrial grade lithium hydroxide is dissolved into pure water or crystallization mother liquor, and a first solution is prepared; a first impurity removal agent is added into the first solution, then filtering is performed, a lithium hydroxide crystal is added into a filtrate, cooling crystallization is performed, solid-liquid separation is performed to obtain a high-purity lithium hydroxide monohydrate wet material and crystallization mother liquor; the high-purity lithium hydroxide monohydrate wet material is dissolved into pure water or carbonization mother liquor, and a second solution is prepared; carbon dioxide is introduced into the second solution to perform primary carbonization, and solid-liquid separation is performed to obtain a lithium carbonate wet material and a filtrate; a second impurity removal agent is added into the filtrate, after a heat preservation reaction is performed, carbon dioxide is introduced to perform secondary carbonization, then, introduction of the carbon dioxide is stopped, the reaction continues to be performed, then, solid-liquid separation is performed, obtained solids are washed, a high-purity lithium carbonate wet material and carbonization mother liquor are obtained, and after the high-purity lithium carbonate wet material is post-processed, a high-purity lithium carbonate product is obtained.