According to the shortage of the current researches of network invulnerability indices, this paper makes research on network reliability and node importance based on invulnerability. By analyzing statistically about network clustering survivability under different node-link reliability, indices of network invulnerability and node invulnerability-network clustering invulnerability and nodal invulnerability are proposed, based on which simulation are processed. The simulation results indicate that the analysis of nodal importance base on nodal invulnerability overcomes the defect of the current methods and is more scientific and accurate.