The invention belongs to the field of photocatalysts and provides a compound photocatalyst material and a preparation method and application thereof. The preparation method comprises the following steps: step 1 of treating urea and a waste paper precursor; step 2 of preparing a binary compound photocatalytic material g-C3N4/C. The invention discloses the binary compound photocatalytic material g-C3N4, a preparation method thereof and application thereof. The g-C3N4 is a novel organic visual photocatalyst; meanwhile, a carbon material has excellent electronic transmission performance; introduction of a carbon-based non-metal material and a synergistic effect of the g-C3N4 improve the photocatalytic effect; thus, the prepared binary compound photocatalyst disclosed by the invention has very good stability and catalytic activity.