The present disclosure relates to a process for preparing an intermediate of antibody-drug conjugate. Compared with the conventional art, the process for preparing an intermediate of the antibody-drug conjugate provided by the present disclosure significantly reduces the feed loss for drug moiety, such as MMAD/MMAE or MMAF, etc., as drug moiety is involved in the last step of the reaction, thereby effectively reducing production costs, as well as increasing production efficiency. In addition, the process provided by the present disclosure is simple, environmentally friendly and suitable for large-scale industrialization.
