The invention discloses a three-dimensional indium coordination polymer containing mixed ligands and a synthesis method and application thereof, relating to three-dimensional indium coordination polymers and synthesis methods and application thereof. The three-dimensional indium coordination polymer containing the mixed ligands is used for solving the technical problem of the existing blue fluorescent organic light-emitting materials that the synthesis cost is high and the thermal stability is poor. The three-dimensional indium coordination polymer containing the mixed ligands has a molecular formula of C66H42In8N6O45 and a structural formula shown in a drawing. The synthesis method disclosed by the invention comprises the steps of putting 2,6-pyridinedicarboxylic acid, terephthalic acid and indium nitrate into distilled water, stirring at room temperature until 2,6-pyridinedicarboxylic acid, terephthalic acid and indium nitrate are mixed uniformly, adjusting the pH value of a system, then, putting the system into a stainless-steel reactor lined with polytetrafluoroethylene, reacting, and then, cooling to room temperature, thereby obtaining a yellow hexagonal crystal, namely the three-dimensional indium coordination polymer containing the mixed ligands. The three-dimensional indium coordination polymer containing the mixed ligands, disclosed by the invention, can serve as a metal organic blue light-emitting material and is applied to the field of preparation of organic light-emitting materials.