Phosphogypsum (PG) is a bulk industrial solid waste generated during phosphoric acid manufacturing. This study investigated a novel phosphogypsum-based geopolymer (PBG) cement through L16(45) orthogonal experiments. The impact of five alkaline activators, including Portland cement clinker (PCC), sulfate alumina cement clinker (SACC), aluminate cement (AC), magnesium oxide (MgO), and calcium oxide (CaO), on the performance of PBG cement was analyzed, and the optimal mix ratio was determined. Results indicate that all four alkaline activators, excluding CaO, can enhance unconfined compressive strength (UCS) of PBG cement. Factor index analysis revealed that an optimal composition comprising 4 % PCC, 6 % SACC, 2 % AC, and 4 % MgO yielded the highest 28-day UCS of 45.63 MPa. PBG cement primarily consists of dihydrate gypsum (CaSO4·2H2O), ettringite (Ca6(Al(OH)6)2(SO4)3(H2O)25.7), and polymers. Of these constituents, the polymers accounted for 61.9 wt% of the total composition and provided most of the strength. This study provided a new approach for making better use of waste PG.