The situation that two identical two-level atoms initially entangled with the third atom are separately trapped in two distant single-mode optical cavities, which are coupled by an optical fiber, is considered. The entanglement between cavities is investigated. By means of numerical calculations, through comparing the results if a direct selective measurement is performed or not, the effect of the state-selective measurement on the entanglement and that of the coupling coefficient between atom and cavity on the entanglement are discussed. The results show that the entanglement between the cavities can be strengthened through the state-selective measurement on the atom outside cavities; if the coupling coefficient between atom and cavity increases, the entanglement between cavities can also be strengthened.