Abstract: Considering that commutation failure analysis of hybrid multi-infeed HVDC transmission system（HMIDC） is mainly performed with simulation tools, a rapid assessment method of commutation failure immunity level for HMIDC is proposed. Firstly, on the basis of voltage stability indicator（VSI）, a rapid determination method of commutation failure immunity level for single-infeed line commutated converter based high voltage direct current（LCC-HVDC） was put forward, and its accuracy was verified by the CIGRE Benchmark Model. Then, an equivalent dual-bus analytical model of HMIDC systems was established, through which an equivalent voltage stability indicator（EVSI） was defined. Meanwhile, the calculation method of EVSI was studied by analyzing converter power-voltage characteristics and phase angle-voltage characteristics. Furthermore, a rapid determination method of commutation failure immunity level for HMIDC systems based on EVSI was set up, and the proposed method was validated by a hybrid dual-infeed HVDC transmission system.