In the simulation, the TSE performances were investigated by using the various- operating conditions in the steam ejector refrigeration system compared with the single-stage ejector (SSE). For the optimum geometry of TSE, the area ratio (A4/A6) was 1.6, the length (L4) was 2.0D4, and the convergence angle (θII) was 4°. The TSE was investigated by adopting the operating conditions from the previous work whose generator temperatures were between 100 °C and 130 °C, and the evaporator temperatures were between 0 °C and 15 °C. The TSE provided a higher entrainment ratio by up to 77.2%, while there was a marginal decrease in critical back pressure up to the maximum value of 21.9%. It can be concluded that the TSE greatly benefited the refrigeration system, which needs high refrigerating capacity while the condensing pressure was slightly subsided.