Let (C, C) be a braided monoidal category. The relationship between the braided Lie algebra and the left Jacobi braided Lie algebra in the category (C, C) is investigated. First, a braided C2-commutative algebra in the category (C, C) is defined and three equations on the braiding in the category (C, C) are proved. Secondly, it is verified that (A, [, ] ) is a left (strict) Jacobi braided Lie algebra if and only if (A, [, ] ) is a braided Lie algebra, where A is an associative algebra in the category (C, C). Finally, as an application, the structures of braided Lie algebras are given in the category of Yetter-Drinfel'd modules and the category of Hopf bimodules.