By employing the negative eigenvalue to describe the entanglement between two systems, the entanglement characteristics between the two cavities and between the cavity and the atomic ensemble in the fiber-coupled cavity model are studied under the condition that both cavities trap atomic ensembles. The effects of the number of atoms contained in the atomic ensemble and the fiber-cavity coupling coefficient on the entanglement characteristics are discussed. The results show that the Rabi oscillation frequency of the entanglement between the two cavities as well as that between the cavity and the atomic ensemble increases with the increase of the number of atoms. As the fiber-cavity coupling coefficient increases, the entanglement between the two cavities as well as that between the cavity and the atomic ensemble is strengthened.