In recent years， studies have found that adolescent obesity and depression generally have a two-way connection， that is， when one situation occurs， the risk of the other situation significantly increases. It is found that the two have a lot in common in genetics， inflammatory factors， hormones and social environment. Analyzing the correlation between the two and its causes in adolescence may not only become an important target for obesity and depression treatment， but also can even prevent the occurrence of both. Yet， more evidence is needed to support this theory. In this paper， the correlation and related causes of adolescent obesity and depression are illustrated.