Abstract: In this study, in order to obtain nylon 66-based composites with low electrical resistivity, carbon fiber-Ni/nylon 66 composites were prepared by a plastic extruder with carbon fiber (CF) and nickel powder (Ni) as the paddings, nylon 66 as the raw resin. The relationships of the surficial modification and the fractions of CF and Ni between the electrical resistivity and mechanical properties of CF-Ni/nylon 66 composites were studied. The results show that the modification by KH550 and increasing of CF and Ni are of advantage to decrease the electric resistivity of CF-Ni/nylon 66 composites. And the electrical percolation thresholds of CF and Ni both are 20 wt%. The electric resistivity of CF-Ni/nylon 66 composite is 455 Ω·cm at the percolation thresholds, and its melting point is 202.2℃. The flexural strength and tensile strength of CF-Ni/nylon 66 composites increase firstly and decrease lately with the increasing of CF and Ni. When the fraction of Ni is 20 wt%, the flexural strength of CF-Ni/nylon 66 composite reaches to the maximum 98 MPa as the fraction of CF is 20 wt%, and the tensile strength reaches to the maximum 70 MPa as the fraction is 10 wt%. When the fraction of CF is 20 wt%, the flexural strength of CF-Ni/nylon 66 composite reaches to the maximum 120 MPa as the fraction of Ni is 30 wt%, and the tensile strength reaches to the maximum 67 MPa as the fraction is 20 wt%.