The stochastic-ow network model has been applied to many real world applications such as information systems, telecommunication systems, transportation systems, and etc. Therefore, the technology of sensitivity analysis for a stochastic-ow network is important in practice. This paper proposes methods for analyzing the node sensitivity with re- spect to the system reliability of a stochastic-ow network. These include increasing-capacity contributivity analysis and decreasing-capacity impairment analysis. The former anal- ysis is in order to check those nodes which contribute reli- Ability most when adding resources into the network. The decreasing-capacity impairment analysis however is in order to inspect those nodes which hurt reliability most when de- creasing resources from the network. Some interesting find- ings are obtained. For example, the strategy of increase ca- pacity will not promise to contribute reliability. The strategy of decrease capacity will also not always to impair reliability. Numerical examples for these analyses are illustrated in this paper.