Abstract To explore the technical alternatives of refrigerant substitution and analyze the application of low GWP refrigerant in three-stage cascade refrigeration system (TCRS), the change of operation parameters with the evaporation temperature has been studied by thermodynamic analysis. The results show that R1150 can replace R14 in low-temperature cycle. R41 and R170 can replace R23 in medium-temperature cycle and R170 will be recommended as a priority. In high-temperature cycle, the refrigerants of R717, R152a and R161 are recommended. Taking into account environmental protection, the natural refrigerant of R717 is a good choice in the large refrigeration system. In particular, the refrigerant groups of R1150/R41/R717, R1150/R41/R152a, R1150/R41/R161, R1150/R170/R717, R1150/R170/R152a and R1150/R170/R161 are recognized. The results provide a basic theoretical analysis of the selection and replacement of refrigerant in TCRS.