The structural, electronic and some magnetic behavior of the tin carbide (SnC) nanoribbons with the substitutional impurity atoms of boron, aluminum, nitrogen and phosphorus are investigated by using density functional theory (DFT) framework. The armchair and zigzag SnC nanoribbons are considered with the 7 and 4 atoms width, respectively. We found that all the four impurities prefer to substitute the Sn atom sites which located at the edge of nanoribbon or close to it. Also, the band structures analysis demonstrated that the impurities create extra bands in the region of nanoribbons band gap. So, the spin-down band gap values of the doped 7-ASnCNRs are reduced to 0.218, 0, 1.043 and 1.233 eV for B, Al, N and P atoms, respectively. Moreover, the half metal behavior is observed for the Al-doped 7-ASiCNR. For the 4-ZSnCNR, the impurity atoms could increase the band gap, especially in the spin-up channel. Finally, they introduce a total magnetic moment of 1 μB into the nonmagnetic 7-ASnCNR and they affect on the magnetic moment of the 4-ZSnCNR.