The morphological, mechanical and rheological properties of poly(trimethylene terephthalate)(PTT)/maleinized acrylonitrile-butadiene-styrene (ABS-g-MAH)/short carbon fiber (SCF) composites were investigated by the scanning electron microscopy(SEM), universal tester, impact tester and capillary rheometer, respectively. The SEM images of the composites’ fracture surface show that the fracture surface is rough and SCF are randomly dispersed in the matrix resin, and there is a good interfacial interaction between SCF and PTT. The composites show the maximum tensile strength when adding 10-23% SCF into PTT/ABS blends. The rheology results show that the composites melt are pseudo-plastic fluid, and the melt apparent viscosity of the PTT/ABS/SCF composites increases with increasing SCF content.