The invention relates to a method for recovering useful ingredients in waste glycin mother liquor, which comprises the following steps: acidifying the waste glycin mother liquor; adding organic solvents to be fully mixed with the waste glycin mother liquor; carrying out the solid-liquid separation for the first time to obtain first filtrate and solid with the useful ingredients; dissolving the solid to separate different useful ingredients through concentration and crystallization; continuously adding organic solvents into the first filtrate to be fully mixed; carrying out the solid-liquid separation for the second time to obtain second filtrate and solid with the useful ingredients; dissolving the solid to separate different useful ingredients through concentration and crystallization; basifying the second filtrate; obtaining third filtrate and solid with the useful ingredients; dissolving the solid again to separate different useful ingredients through concentration and crystallization; and carrying out other steps. The invention can more sufficiently utilize the waste glycin mother liquor as resources, simplifies the subsequent separation and refining processes on the useful ingredients, lowers the process difficulty for treating residual liquid, can recover and reuse the used organic solvents, and greatly reduces the environment pollution by the waste glycin mother liquor.