In this study, we have investigated the adsorption and dissociation of four small gas molecules including HCOH, H2S, NH3, and O2 on Al12P12 fullerene using density functional theory (DFT). The computations have been performed with B3LYP-D and M06-2X levels of theory and have been calculated with the 6-311++G** basis set. The adsorption of HCOH, H2S, NH3, and O2 molecules can be attributed to the chemical and physical behavior of these molecules. The computational results show that the dissociation energies of HCOH and H2S on the surface of Al12P12 fullerene were found more negative than those of their adsorption. On the contrary, the adsorption energies of O2 and NH3 on the surface of Al12P12 fullerene were found to be more negative than those of their dissociation. The results also indicate that the differences between calculated energies at both levels are negligible. The complex bonds between all molecules and Al12P12 fullerene have been formed due to the charge transfer that occurred during these interactions. According to the computations and the plots of total density of state (TDOS), the results indicate that Al12P12 fullerene is slightly sensitive toward HCOH and H2S molecules.