One method to improve the performance of vapor compression refrigeration system using subcooling and environmentally friendly refrigerant. Hydrocarbon refrigerant is one of the environmentally friendly refrigerants that are proven to improve the performance of vapor compression system without sub-cooling. To that end, this for study aimed to analyze the effect is liquid-suction sub cooller and cooling load on the performance of the vapor compression refrigeration. Refrigerant R134a and R600a are used, the cooling load variations using lamps. Sub-cooling heat exchanger mounted between condenser and expansion. Variations in the mass amount of refrigerant through the sub-cooling is used the valve. The greater the sub-cooling temperature, the greater the temperature drop in the evaporator, and the cooling effect increases, and the cooling effect with refrigerant R600a is greater than R134a. The increase in compressor work is not affected by the magnitude of the cooling load, but is influenced by the amount of capacity sub-cooling. The greater the sub-cooling and cooling load, the greater the increase in compressor work. Use of sub-cooling effect COP increase and the increase COP R600a is greater than the COP R134a. Broadly speaking that R600a can be used as a substitute refrigerant R134a.