Solar still is processes that can be used to convert available water into clean water. To find out whether the exergy used in the evaporation process has been used optimally in terms of quality, the second law of thermodynamics is used or known as exergy analysis. The purpose of this study was to determine the magnitude of exergy and exergy efficiency of a double slope passive solar still. The results showed that the solar intensity, water temperature, and ambient temperature affected the magnitude of exergy and exergy efficiency. The higher the solar intensity and the temperature of the water, the higher exergy and efficiency of the exergy, and the higher the ambient temperature, the exergy of evaporation in the system will be lower. The daily exergy varies from 0.021 kWh to water temperature and average solar intensity 32.26 °C and 97.9 W/m2 to 0.525 kWh for water temperature and average solar intensity 45.42 °C and 420.855 W/m2 and exergy efficiency varies from 0.928% to 5.363%.