The invention relates to a flexible carbon electrode and application thereof in a lithium ion battery. The flexible carbon electrode is mainly characterized in that the electrode consists of two components, namely micron-grade carbon granules and graphene. The electrode is good in flexibility and can be directly used as an electrode of a lithium ion battery. The carbon granules are adopted as a main active material which accounts for 75-95% of the total mass of the electrode, and the graphene is adopted as an adhesive, a conductive agent and an auxiliary active material which accounts for 5-25% of the total mass of the electrode. A cross-linking structure formed by the graphene in the self-assembling process can play a role of adhesion, the graphene is assembled and molded with the carbongranules, and thus the electrode is good in flexibility. Due to the high conductivity of the graphene, the graphene can be used as a conductive agent of a conventional electrode, and in addition, a carbon/graphene composite flexible electrode is a full-carbon electrode, so that an insulating polymer adhesive PVDF (Polyvinylidene Fluoride) is avoided, and the electric conductivity of the whole material is improved. A graphene flake layer can be also used as an auxiliary active material for providing a part of active specific capacity, and thus the capacity of the electrode is further increased.