Due to the concern on global warming, refrigerants having high GWP(Global Warming Potential) are being replaced to low GWP refrigerants. As for small slush maker, R-134a is being to replaced to R-290, whose GWP is 3. In this study, performance tests were conducted on the slush maker having dual evaporator, which was designed to operate using R-290. Results showed that the optimum refrigerant charge amount was 100g. At the charge amount, 61 minutes was needed to make a slush from a raw milk substance, which contained 10% sucrose. The power consumption was 0.89 kW, which yielded COP of 0.252. Tests were further conducted changing the outdoor air temperature. It was resulted that slush-making was possible at all outdoor temperatures except at an extreme temperature of 43°C. Even at the temperature, slush-making was possible if the machine operated with a single evaporator. The COP increased with the decrease of the outdoor temperature.