The embodiment the invention provides a fault identifying method and device. The method comprises the steps that the structural quantitative three components of each data point in a seismic data body are determined; the structural quantitative matrix of the data point is constructed according to the structural quantitative three components of each data point; the eigenvalue and eigenvector of the structural quantitative matrix of each data point are determined; the fracture attribute value of the data point is determined according to the eigenvalue and eigenvector of the structural quantitative matrix of each data point; a fracture attribute data body is constructed according to the fracture attribute value of each data point; and fracture extraction is carried out on the fracture attribute data body according to the eigenvector of the structural quantitative matrix of each data point. According to the embodiment of the invention, the small fault identification accuracy can be improved, and small faults can be effectively identified.