|Abstract:Poly(ethylene terephthalate) (PET) polyamide 66 (PA66) composite fibrids were prepared by precipitation method. The effects of PA66 content on surface morphology, sizes, hydrophilicity and compatibility of composite fibrids and between PET and PA66 were investigated. What’s more, the strength properties of PET composite paper were also investigated. The results indicated that the surface morphology of the PET-PA66 composite fibrids was ribbonlike, with some wrinkleson the surface.With the increase of PA66 content, the fiber size decreased, the specific surface area of composite fibrid increased from 7.38 m2/g to10.12 m2/g, and the contact angle of composite fibrids decreased from 107 ° to 88 °. There was only one melting peak on the DSC curve which indicated that between PET and PA66 had good compatibility, and the stretching vibration peak at 1724.3 cm-1 in the FT-IR spectrum moved toward the low wave number direction, it indicated that the hydrogen bond between the two polymers was produced during the dissolution process, and the compatibility of the PET-PA66 system increased. With the increase of PA66 content, tensile index and tear index of PET composite paper increased 12.0% and 47.8%, respectively.