The invention discloses a conjugated microporous polymer, and a preparation method and application thereof. The preparation method of the conjugated microporous polymer comprises the following steps:under the atmosphere of argon or nitrogen, mixing a compound II, a compound III, cuprous iodide and a palladium catalyst into an diisopropylamine / organic solvent mixed solution, and uniformly carryingout stirring at room temperature; carrying out ultrasonic dispersion, carrying out freezing and deoxidizing, then carrying out heating to 50-120 DEG C, and carrying out a reaction for 24-72 hours; and carrying out cooling to room temperature, and carrying out filtering, washing and drying. An ion-loaded nano-composite catalytic material is prepared by taking the conjugated microporous polymer asa carrier to load nano-silver particles. The composite catalytic material can be used for efficient catalytic reduction of industrial pollutant p-nitrophenol, and the industrial pollutant p-nitrophenol is converted into common medicines and chemical raw material p-aminophenol. In addition, the catalyst has good solvent tolerance, stability and recyclability.