The invention belongs to the field of gas-solid fluidized bed reactors, and relates to an acousto-optic coupling annular gap photocatalytic fluidized bed VOCs (volatile organic compounds) degrading device. A main body comprises a gas outlet, a gas inlet, a gas inlet pre-distribution plate (inner ring) and a catalyst grain baffle plate (outer ring), an organic glass tube, a quartz glass tube, an ultraviolet lamp, a reactor gas inlet distribution plate, a lamp tube mounting base, a test port, a loudspeaker, a fan, a gas collocation device, a sound wave amplifier, a signal generator, a gas collecting chamber, a gas premixing chamber, a gas inlet passage, an annular gap fluidized bed reaction area and a gas distribution chamber; and the devices form the photocatalytic gaseous contaminant VOCs degrading device with a columnar nested structure through principle reliability combination. The device has the advantages of wide operation area, reliable and convenient operation, simple regeneration of catalyst grains, low oxidation selectivity on gaseous contaminants, good treatment effect and prominent stable fluidization; and reactors can be connected in series or in parallel for use, and the device is suitable for high-concentration VOCs places.