As we know, dynamic VAR compensator can quickly and effectively increase the system dynamic reactive power reserve, thereby improving the transient voltage stability of the system. In this paper, in view of the fact that the dynamic load characteristic based on induction motor load has growing influence on the system transient voltage stability, indexes based on induction motor load characteristics are proposed. The proposed indexes include multi-fault one-node voltage stability index and system voltage stability index. After the dynamic VAR compensator is installed for an actual power grid, the proposed indexes can be applied to assess the transient voltage stability of any node or the whole system to select the optimal allocation location. Tests carried out on IEEE-39 system illustrate the effectiveness of the proposed indexes when they are applied to the quantitative assessment of transient voltage stability in actual system for selecting the optimal allocation location.