In view of a solution of relation triplet overlapping in the extraction process, a joint extraction model of entity relation based on location-aided marking has thus been proposed. Taking BERT as the pre-trained language model, by means of position-aided matrix, the relation triplet extraction is transformed into the matching of entity and relation, thus realizing the joint extraction of entity and relation, with relevant experiments to be carried out on the Chinese data-set DuIE. The experimental results show that the model exhibits an improved performance in extraction, showing that the proposed location-aided marking method can effectively solve the problem of overlapping.