Antimony　selenosulfide　(Sb-2(S,Se)(3))　solar　cells　have　achieved　an　efficiency　of　over　10.0%.　However,　the　uncontrollable　hydrothermal　process　makes　preparing　high-quality　Sb-2(S,Se)(3)　thin　films　a　bottleneck　for　efficient　Sb-2(S,Se)(3)　solar　cell.　To　address　this　problem,　triethanolamine　(TEA)　additive　is　innovatively　utilized　to　regulate　the　reaction　kinetic　process　of　Sb-2(S,Se)(3)　thin　films　in　this　work.　The　results　show　that　TEA　chelator　can　realize　the　time-domain　control　of　the　reaction　process,　optimizing　the　Se/(S+Se)　elemental　distribution　of　Sb-2(S,Se)(3)　thin　film　and　shrinking　the　bandgap　offset　of　Sb-2(S,Se)(3)　thin　film.　Meanwhile,　the　(021)　and　(061)　crystal　orientation　of　Sb-2(S,Se)(3)　thin　film　are　enhanced　and　the　harmful　V-Se1　defects　in　Sb-2(S,Se)(3)　solar　cells　are　passivated.　Interestingly,　a　uniform　back　surface　gradient　for　Sb-2(S,Se)(3)　thin　film　is　formed　to　reduce　the　minority　carrier　recombination　at　the　back　contact,　increase　the　photocurrent　and　decrease　the　diode　current　of　Sb-2(S,Se)(3)　solar　cells.　Finally,　the　J(sc)　and　FF　of　Sb-2(S,Se)(3)　solar　cells　are　significantly　improved　by　8.6%　and　5.5%　respectively,　and　the　open-circuit　voltage　deficit　of　the　device　is　reduced　by　44　mV,　which　leads　to　an　efficiency　of　9.94%　which　is　the　highest　values　of　Sb-2(S,Se)(3)　solar　cells　by　sodium　selenosulfate　system.