Bivalent and trivalent Eu ionsco-doped SrSO4 phosphors were synthesized via the precipitation method by using trivalent Eu ions as the sole dopant source. The crystal structure, morphology and photoluminescence of the synthesized SrSO4 phosphors were investigated by the X-ray diffractometer, scanning electron microscope and spectrophotometer, respectively. It was found that the resultant SrSO4 microcrystals are co-doped with both the bivalent Eu ions and the trivalent Eu ions. The typical size of the SrSO4 microcrystals is in the range of 1~10 μm. Under the ultraviolet excitation of 325 nm, the synthesized SrSO4 microcrystals can give off strong purplish pink photoluminescence, which consists of a broad emission band centered at 379 nm and three narrow emission peaks at 575, 591 and 612 nm, respectively. The bandstructures and defect level of SrSO4 are calculated with density functional theory in the framework of local density approximation, and the photoluminescence mechanisms of the bivalent and trivalent Euco-doped SrSO4 are discussed in terms of the calculated bandstructures. The broad emission band centered at 379 nm can be attributed to the transition 4f65d1→ 4f7 of the bivalent Eu ions in the SrSO4 matrix while the three sharp emission peaks at 575, 591 and 612 nm can be assigned to the transitions of trivalent Eu ions from its excited state 5D0 to its ground states 7F0, 7F1 and 7F2,respectively. It has demonstrated that bivalent Eu and trivalent Euco-doped SrSO4 can be utilized as an efficient purplish pink phosphors.