A variety of stress cracks appear in the garment seam, which affects the appearance and the seam strength. In this paper, the indicating methods of seam cracks were presented by identification and analysis of a variety of seam cracks on woven garments. The regression equation of seam crack recognizable rate was listed through different kinds of seam cracks observed and distinguished by inspectors. The influence on crack recognizable rate by the size and the colour of the crack was also analyzed in this paper. The objective assessment of fracture strength was made by testing the fracture strengths of five kinds of fabrics in warp, weft and 45 ° oblique direction using self-made needle crack testing device. This paper has certain significance for fabric designing and clothing production technology.