The invention relates to a refrigerant flow control method and system and a refrigerator. The method includes the steps of collecting the environmental temperature and the degree of superheat of an evaporator in real time; setting the number of valve opening pulses of an electronic expansion valve to be the preset number of valve opening pulses according to the current environmental temperature; determining the modified value of valve opening pulses according to the collected real-time degree of superheat and the prestored standard degree of superheat; using the sum of the preset number of valve opening pulses and the modified value of valve opening pulses as the number of operation valve opening pulses, and adjusting the operation opening degree of the electronic expansion valve according to the number of operation valve opening pulses; and controlling the refrigerant flow through cooperation of a capillary tube and the electronic expansion valve. The opening degree of the electronic expansion valve is controlled through the environmental temperature and the temperature of an inlet and an outlet of the evaporator, so that the effect of controlling the refrigerant flow accurately according to the system loads is achieved, and the response speed of the refrigerator to changes of thermal loads is increased; and through cooperation of the electronic expansion valve and the capillary tube, the refrigerant flow of the system can be adjusted, and all kinds of loads can be dealt with efficiently.