The present disclosure relates to a photoetching parameter adjustment method, apparatus and mask plate, in the field of photoetching technology. The method comprises: forming a photoresist pattern on a first substrate by a photoetching process, wherein the photoresist pattern comprises a photoetching detection pattern; judging whether photoetching parameters of the photoetching process need to be adjusted or not in accordance with the photoetching detection pattern; and adjusting the photoetching parameters when the photoetching parameters need to be adjusted. The present disclosure solves the problem that the reliability of the photoetching parameters is low and improves the reliability of the photoetching parameters. The present disclosure is used for adjusting photoetching parameters.