The invention discloses a shopping bag discharging machine and a bag discharging method. The shopping bag discharging machine is used for automatically discharging shopping bags and comprises a pressing roller assembly, a bag clamping assembly, a pushing device assembly and a bottom plate, the pressing roller assembly, the pushing device assembly and the bag clamping assembly are arranged on the bottom plate, the pressing roller assembly comprises a movable pressing roller and a fixed pressing roller, and the bag clamping assembly comprises bag clamping pieces and bag clamping side plates. The bag clamping pieces and the movable pressing roller are arranged on the pushing device assembly, the movable pressing roller tightly presses the fixed pressing roller through stretching of the pushing device assembly, the fixed pressing roller rolls to send out the shopping bag, and when the pushing device assembly contracts, the bag clamping pieces clamp the shopping bag and tightly presses the shopping bag on the bag clamping side plates so that a customer tears down the shopping bag conveniently. According to the bag discharging machine, through linkage of the movable pressing roller and the bag clamping pieces, the pressing roller assembly and the bag clamping assembly clamp and loosen the shopping bag respectively, the shopping bag is enabled to be in a rolling bag discharging state and a clamping bag tearing state, the structure is simple and reliable, meanwhile, the shopping bag can be automatically rectified, and it is guaranteed that a bag rolling fault does not occur in the next bag discharging process.