Obesity is always been considered as a risk factor for acute lung injury (ALI). Although obese patients have an increased risk of lung injury, their mortality is lower than patients with normal weight. This phenomenon is called the "obesity paradox" and this mechanism involved is not fully understood. This article reviews recent studies concerning obesity‑related ALI, from the perspectives of the generation of the "obesity paradox", the possible causes of obesity aggravation and alleviation of ALI, and the possible mechanism of the "obesity paradox", and summarizes the research progress on the "obesity paradox" of ALI. The study is expected to provide a theoretical basis for the clinical prevention and treatment of obesity‑related ALI, and provide reference for the protection of other important organs.