Abstract: In order to investigate the spinning process of conducting fibers,the properties of polyester composites filled with conducting carbon black(CB) have been examined by differential scanning calorimetry,thermo-gravimetric analysis,ohmmeter,and rheometer.The results reveal that with increasing of the weight of CB in the composites,the glass transition temperature,melting temperature of CB/PET composites dropped slightly,but the crystallization temperature decreased remarkably,thermal stability of the CB/PET systems is enhanced,and the surface resistivity tends to saturation.The electrical conductivity of conducting composites is related to the dispersed state of CB particles in composites,and their spinning performance becomes poorer with increasing of the weight of CB.