Disclosed is a test method for gentamicin in pharmaceutical solid waste.The test method includes: (1) collecting gentamicin in solid waste samples, mixing cation exchange resin into the solid waste samples, adding water for dissolving, performing intensive mixing when PH=6.6-7, collecting the cation exchange resin, and washing with water; putting the dried resin into a container, adding ammonia water of a certain concentration into the container, eluting the gentamicin adsorbed in the cation exchange resin after mixing, collecting eluent, cleaning the resin and the container with the ammonia water, combining cleaning solution with the eluent, removing ammonia and moisture by evaporation, and collecting solid gentamicin; (2) adding a known quantity of standards into the waste samples, and acquiring the solid gentamicin according to the step (1); (3) dissolving the gentamicin in the step (1) and (2) with moving phase, and performing constant volume filtration to obtain samples to be tested and recovery-rate samples; (4) respectively injecting the standards, the samples to be tested and the recovery-rate samples so as to measure gentamicin C components in the samples.The method has feasibility via verification.