Low-carbon alcohols have been universally acknowledged as an alternative to fossil fuel in the world, which is environmentally friendly and clean. In this paper, the detailed exergy and energy analysis was carried out on a turbocharged, spark-ignition (SI) engine fueled with methanol−ethanol−gasoline (GEM) under non-knock conditions. The results indicated that increasing the alcohols proportion in blends could slightly improve the exergy efficiency and thermal efficiency and increase the percentage of total irreversibility in the total exergy. The thermal efficiency and exergy efficiency increased to a maximum value and then decreased, while the proportion of total irreversibility in the total exergy increased significantly with the spark timing retarded from the earliest timing. The exergy efficiency and thermal efficiency increased as the engine load increased. Additionally, the total irreversibility increased but the proportion of total irreversibility in the total exergy presented a trend of decreasing as the engine load increased.