This paper present the thermodynamic performance evaluation using Energy-Exergy method for cascade vapour-compression refrigeration system by using for HFO-1234yf (2, 3, 3, 3-Tetrafluoropropene) in the low temperature circuit and HFO-1234ze (trans-1, 3, 3, 3-tetrafluoroprop-1-ene) in the high temperature circuit. Both HFO refrigerants have ultra-low Global Warming Potential (GWP) with zero Ozone Depletion Potential (ODP) and comparison was made of the computed results using HFO refrigerants with HFC-134a refrigerant as possible alternative replacements in low temperature refrigeration circuit in the range evaporator temperature variation between -35oC of -50oC. A numerical computation has been carried out for calculating first law efficiency in terms of system coefficient of performance... (SCOP), Second law efficiency in terms of exergetic efficiency, exergy destruction ratio based on exergy of fuel and also exergy destruction ratio based on exergy of product, first law efficiency for high temperature circuit and first law efficiency for low temperature circuit, power required to run whole system and power required for each compressors, mass flow rate in each evaporators with variation of high temperature condenser temperature ranging between 30oC to 55oC and cascade evaporator temperature ranging between -20oC to 20oC using HFO1234ze along with effect of temperature overlapping in terms of approach. It was observed that Cascade Refrigeration system gives comparable thermal performances which can replace HFC-134a in the low temperature applications and efficiency defects for HFO-1234yf, HFO-1234ze and HFC-134a. During the investigation, condenser temperature is kept at 313K and evaporator temperature is kept in the range from 223K to 273K .Results obtained indicate that HFO-1234yf and HFO-1234ze can be good replacement of R-134a. Among the system components, condenser shows highest efficiency defect value and low temperature evaporator shows the lowest.