Taking the literatures on the relationship between TPH gene polymorphism and unipolar depression both in China and abroad as research objects, using the software of RevMan 50, the paper comprehensively evaluates the relations between TPH gene polymorphism and unipolar depression. The results show that TPH gene polymorphism has significant associations with unipolar depression, CC genotype increases the risk for unipolar depression, AA and AC genotypes are not significantly associated with unipolar depression.