Purpose No adequate study on scientific analysis of surface metal fiber (SMF) arrangement of electromagnetic shielding fabric (EMSF) and influence on shielding effectiveness (SE) is available at present. Design/methodology/approach This paper recognizes the SMF region and constructs a binary feature matrix according to edge condition, width condition and gray condition using the computer image analysis technique based on the construction of the surface digitized image of the EMSF. Three parameters of coverage, dispersion and uniformity are proposed to describe the SMF arrangement. Then experiments and testing samples are designed to analyze the relationship between the three parameters and the SE. Findings Results show that the proposed method can accurately recognize the SMF of the EMSF, the coverage, dispersion and uniformity can describe three aspects of the SMF arrangement of percentage content, porosity and orientation, and the three parameters are positively, negatively and positively correlated to the SE, respectively. Originality/value The research in this paper provides the basis for further description of the SMF arrangement of the EMSF, possesses the significance for the study of the shielding mechanism, transmission model, electromagnetic performance and rapid non-destructive evaluation of the EMSF and provide a new idea for the study on the shielding theory and application of the EMSF.