This paper describes the electrical properties of poly (polycrystalline) 3C-SiC thin films with different nitrogen doping concentrations. In-situ doped poly 3C-SiC thin films were deposited by APCVD at $1200^{circ}C$ using HMDS (hexamethyildisilane: $Si_2(CH_3)_6)$) as Si and C precursor, and $0{sim}100$ sccm $N_2$ as the dopant source gas. The peak of SiC is appeared in poly 3C-SiC thin films grown on $SiO_2/Si$ substrates in XRD(X-ray diffraction) and FT-IR(Fourier transform infrared spectroscopy) analyses. The resistivity of poly 3C-SiC thin films decreased from $8.35{Omega}{cdot}cm$ with $N_2$ of 0 sccm to $0.014{Omega}{cdot}cm$ with 100 sccm. The carrier concentration of poly 3C-SiC films increased with doping from $3.0819{ imes}10^{17}$ to $2.2994{ imes}10^{19}cm^{-3}$ and their electronic mobilities increased from 2.433 to $29.299cm^2/V{cdot}S$, respectively.