The utility model provides a device for collecting waste gas in the wet granulation of carbon black. The device is sequentially connected with a pulse-type bag filter, a micron-scale grinder, a fan, a separator and a wet granulator via air-conveying channels; the wet granulator is connected with a dryer mounted in a dry fire box; the dry fire box is connected with a tail gas combustion furnace; the dryer is sequentially connected with a waste gas exhaust fan via waste gas channels; and the waste gas exhaust fan is connected with the pulse-type bag filter. Accordingly, the utility model has the following technical effects that: 1, the utility model can save the investment on devices and the cost for maintenance and operation and achieve obvious effects of energy conservation and expenditure reduction; 2, the utility model can improve the capacity in blowing down carbon black attached to the surface of the bag filter and maintain the good air permeability of the bag filter; 3, the utility model can save the fuel (the tail gas of carbon black) of the tail gas combustion furnace and save the energy; and 4, the utility model can greatly reduce the failure rate of the bag filter and prolong the service life of the bag filter for the waste gas, thus greatly reducing the labor intensity of the operators.