Abstract: The network invulnerability is the capacity that the network maintains it’s function when it suffers some initiative attacks. The network invulnerability is not only an important index in the evaluation of network security, but also important in research of network attack. At present, there are different methods in measurement of invulnerability here. Based on the fundamental indices of network and combined with effect evaluation of network attack, this paper brings forward the measurement of network invulnerability.

Key words: invulnerability, effect evaluation, rough set