Abstract: To address the limitation of existing short-circuit ratio metrics in accounting for the influence of flexible external characteristics across different devices, this paper proposes a comprehensive metric called the hybrid equivalent short-circuit ratio for evaluating static voltage stability in multi-infeed power systems. First, the Jacobian matrix on the network side and the device side is derived. The relation between the traditional multi-infeed short circuit ratio and the Jacobian matrix is analyzed, which reveals the essence that the critical value of the traditional multi-infeed short-circuit ratio is difficult to be unified. Then, based on the singular boundary of the system Jacobian matrix, the multi-infeed short-circuit ratio is extended to various equipment application scenarios, and a hybrid equivalent short-circuit ratio index is proposed, which can consider the influence of different equipment external characteristics. Finally, considering the influence of equipment control mode, line impedance angle and other factors on the index, the qualitative analysis is carried out. The simulation example shows that the proposed index can accurately evaluate the static voltage stability of multi-infeed power systems.