In order to explore the dynamics and distribution properties of quantum coherence in cavity quantum electro dynamics system, a system was built by connecting two cavities through an optical fiber, where an atomic ensemble could be trapped in each cavity. By employing the quantum relative entropy measure of quantum coherence and introducing the concept of quantum coherence imbalance, the coherence dynamics of the system and the influence of the fiber-cavity coupling strength on the coherence distribution were studied. It is found that the global coherence of the atoms in the two cavities preserves well in the strong coupling limit by increasing the fiber-cavity coupling strength, and perfect transfer of atomic coherence from one cavity to the other cavity can be realized under specific configurations for the fiber-cavity coupling strength, the atom-cavity coupling strength and the atom number. Considering the presence of dissipations for the cavities, fibers and atoms, the evolutions of coherence under different dissipation rates with that in the non-dissipation case were compared. It is shown that the coherence of the coupled two-cavity system and the atomic coherence in each cavity are both reduced by dissipations.