Abstract: In order to develop new fabrics involving PTT fiber,the heat settings of PTT fabrics with different elongation under different temperatures were carried out.The influence of heat setting process on the performance of PTT fabrics was investigated.The XRD analysis was used to characterize the changes of crystallinity within the fiber influenced by heat setting.The experimental results showed that the strength and elasticity recovery ratio of PTT fabrics basically increased with rising of the temperature and increase of the fabric elongation,while the softness became worse.The crystallinity of PTT fiber was found being changed by the heat setting.In conclusion,the heat setting around(170 ℃) with an elongation of about 5% would be helpful in improving the performance of PTT fabrics.