According to the spray-quench chamber’s size and operating conditions, three different pressure atomization nozzles were designed. The effects of the operating differential pressure on the nozzle’s flow, droplet size distribution and spray angle were investigated, the variation of the droplet size distribution at different spray distance was researched, and the atomization characteristics of the three kinds of nozzles were also compared. The results showed that when the differential pressure increased to 0.28 MPa, the change in droplet size distribution became flatter and the increase of spray angle was also more difficult. The droplet size distribution first decreased, then increased with the spray-distance at low pressure differential; at high pressure differential, it decreased with the spray-distance. Among the three kinds of nozzles, nozzle 3 performed the best, and nozzle 3 would be chosen as the nozzle of the following spray-quench chamber’s large-scale cold model experiments.