The invention relates to an efficient secondary arc-shaped dust removing and flow equilibrating device of a square-box type desulfurizing tower. The efficient secondary arc-shaped dust removing and flow equilibrating device comprises a plurality of arc-shaped dust removing and flow equilibrating plate modules which are horizontally arranged along the cross section of the desulfurizing tower and are connected into a whole, wherein each arc-shaped dust removing and flow equilibrating plate module comprises a plurality of steel plates longitudinally arranged in parallel, each steel plate is a bent plate with an arc groove in the middle, and the steel plates are arranged equidistantly; triangular dustproof plates are arranged in the connection positions of the arc-shaped dust removing and flow equilibrating plate modules. In the efficient secondary arc-shaped dust removing and flow equilibrating device, gas flow performs rotary disturbance, gas and liquids are more sufficiently contacted, the desulfurizing reaction area is increased, meanwhile, smoke and gypsum slurry in the gas and liquids are removed, and the dust removal purpose is achieved.