In order to find out the factors influencing the extensibility of knitted piping around collars,six knitted fabrics with different properties were selected and used for experiments under various sewing conditions.The experimental results revealed that fabric property had greater impact on the extensibility of knitted piping around collars,which was correlated well with the course density,wale density and elongation at break.The greater the course density,wale density and elongation at break,the better the extensibility.The extensibility was negatively correlated with the linear density.The closer the linear density,the better the extensibility.When the fabric and stitch density were the same,the extensibility of single-needle sewn piping around collar was better than that of the double needle sewn.When the fabric and number of needle were the same,the closer the stitch density,the better the extensibility.