▎ 摘　　要

Large magnetic anisotropy energy and out-of-plane easy magnetization direction are beneficial for the application of 2D ferromagnetism. Although the robust room-temperature ferromagnetism is reported in Co-N-doped graphene [Nat. Commun. 2021, 12, 1854], its magnetic anisotropy and easy axis of magnetization are still unclear. Herein, the magnetic anisotropy of CoN4-graphene and CoN3-graphene is systematically studied. The CoN4-graphene has an in-plane easy magnetization direction, while the easy magnetization direction of CoN3-graphene is out-of-plane. The magnetic anisotropy energy can be tuned by injecting charge or applying strain. Especially, for CoN3-graphene, both charge injection and tensile strain can tune the easy magnetization direction from out-of-plane to in-plane. The tunable magnetic anisotropy may promote the application of Co-N-doped graphene in spintronic devices.