In this work, a novel ternary Z-scheme photocatalyst, NiGa2O4/NiS2/WO3, is prepared by sol-hydrotherma and calcination methods. The photocatalytic performance of prepared photocatalyst is evaluated through the simultaneous conversions of NO2- and SO32- under simulated solar-light irradiation. At the same time, the effects of solution acidity, simulated solar-light irradiation time, e(-) and h(+) scavengers, used times and photocatalyst species on photocatalytic conversions of NO2- and SO32- are also studied. Due to the presence of NiS2 as conducting pathway, which can quickly transfer photo-generated electron (e(-)) and efficiently promote separation of electrons (e(-)) and holse (h(+)), the prepared ternary Z-scheme photocatalyst, NiGa2O4/NiS2/WO3, exhibits excellent performance in the simultaneous conversions of NO2- and SO32- under simulated solar-light irradiation. The conversion ratios of NO2- and SO32- can reach 87.03% and 97.47% under optimal experimental conductions, respectively.