To quickly evaluate power system static stability under single branch contingency， based on vulnerability theory of complex network， a complementary vulnerability index set and an integrated vulnerability index are presented to assess the vulnerability of transmission branches under edge attacking from the aspect of active power and reactive power using global and local indexes. The complementary index set is composed of the global and local indexes. Firstly， a global index， the average transmission distance， is introduced to estimate the active power transmitting efficiency. Secondly， the local variation indexes are proposed to estimate the reactive power balances of power systems. The integrated vulnerability index is defined as the weighted sum of the complementary index set. Simulation results on IEEE 30 testing system indicate the effectiveness of the proposed vulnerability assessment method.