A capillary driven ejector refrigerator is a new refrigeration system that can use solar energy and other low-grade heat sources. In this paper, the performance of the refrigeration system is simulated numerically by use of an iteration algorithm and block exchanging technology for all unit models. The flow and heat transfer characteristics in a solar collector, generator, ejector, condenser, and evaporator are analyzed and calculated. The results show that when the generating temperature is higher than 75-80 degrees C and the environmental temperature is lower than 35 degrees C, the system can work normally; the coefficient of performance of this refrigeration system is in the range of 0.05-0.15 by use of water as a refrigerant. The cooling capacity and COP increase with an increasing generative temperature and decreasing condensing pressure.