The invention discloses a preparation method and application of an iron-sulfur co-modified graphite phase carbon nitride compound, and belongs to the technical field of environmental engineering. Specifically, thiourea and ferric chloride are used as precursors, and the iron-sulfur co-modified graphite phase carbon nitride is prepared by adopting a pyrolysis method. The prepared iron-sulfur co-modified graphite phase carbon nitride compound is used for activating peroxymonosulfate so as to remove tributyl phosphate. According to the method provided by the invention, the removal rate of tributyl phosphate reaches 100%, no precipitate is formed, the survival time of sulfate radical free radicals in water is long, the selectivity is relatively high, and the disclosed compound can adapt to a wider pH range.