Recent angle resolved photoemission spectroscopy (ARPES) experiments have suggested that BiS2 based superconductors are at very low electron doping.Using random phase approximation (RPA) and functional renormalization group (FRG) methods, we find that g-wave pairing symmetry belonging to A2g irreducible representation is dominant at electron doping x < 0.25.The pairing symmetry is determined by inter-pocket nesting and orbital characters on the Fermi surfaces and is robust in a two-orbital model including both Hunds coupling J, and Hubbard-like Coulomb interactions U and Uwith relatively small J (J< 0.2U).With the increasing electron doping, the g-wave state competes with both the s-wave A1g and d-wave B2g states and no pairing symmetry emerges dominantly.