考虑将W态中的两个二能级原子分别注入耦合腔A和B中，并且原子与腔场发生共振相互作用的情况。利用Negativity熵来描述两子系统间的纠缠，采用数值计算方法研究了腔内原子与原子间、腔场与腔场间和原子与腔场间的纠缠特性。通过对是否进行腔外原子选择性测量的结果的比较，讨论了原子选择性测量对纠缠性质的影响。研究了腔场间的耦合强度变化对纠缠特性的影响。研究结果表明，对腔外原子的选择性测量，可增强腔内原子间、腔场间和原子与腔场间的纠缠。

The W state of three two-level atoms, two of which are separated into two initially empty coupling cavities, is considered. The temporal evolution in the entanglement between the atoms, between the cavities, as well as between the atom and the local cavity mode is numerically studied. Through comparing the results if a direct selective measurement is performed or not, the influences of state-selective measurement of the atom outside cavities on entanglement are investigated. The influences of cavity-cavity coupling coefficient on the entanglement is also investigated. The results show that the entanglement can be strengthened through the state-selective measurement on the atom outside the cavities.