Abstract: On the basis of diagonal spinning theory, spinning triangle shape variation model was built to analyze the influence of spinning triangle shape change on ring spun yarn properties, especially yarn hairiness; corresponding mechanism was discussed. For validating the theoretical analysis, several experiments such as conventional and diagonal spinning were conducted to get various spinning triangle change on different type ring frames respectively; spun yarns properties were comparatively studied. Experimental results indicated that yarn guidance path and twist transport were very essential to deformation of spinning triangle shapes; the diminished spinning triangle yielded yarn with improved surface and mechanical properties. In all, the experimental results agreed with the theoretical analysis.