In this paper, we investigated SO2 adsorption on B, N, P and Al doped MoS2, which band structure, density of states, charge transfer, etc by the density function theory (DFT) calculation. Results show that the SO2 prefer to be absorbed at the top of Mo atom of MoS2. It is found that SO2 is strongly adsorbed on Al-MoS2 with considerable adsorption energy of -1 to -2.33 eV, however, the best adsorption position is the top of Mo atom of Al-MoS2, which the biggest E-a is -2.33 eV, the best charge is -0.343e and the shortest d is 1.763 angstrom. So these findings confirm that Al-MoS2 can be used to detect the presence of SO2 in the environment.