The invention provides a method for measuring a strength index of interaction between converter stations of a multi-feed direct current system. The method comprises the following steps that (1)a multi-feed alternating current and direct current power grid receiving end system is taken as a research focus, direct current converter stations to be researched are determined, and it is assumed that the number of the direct current converter stations to be researched is N, and the direct current converter stations to be researched have three phases of A, B and C; (2) electromechanical transient simulation calculation is conducted on the power grid with electromechanical transient simulation software, a single-phase grounded short circuit with certain resistance is arranged at the phase A at a converter bus i, i=1, 2, ...N, the change of the voltage of the phase A at the converter bus i is observed, the grounded resistance of the short circuit is adjusted constantly, the voltage of the phase A at the converter bus i drops by 1% after the short circuit, the variation delta UAj of the voltage of the phase A at the converter bus j is recorded, j=1, 2, ..., i-1, i+1, ...N, and the calculation of the phase B and the calculation of the phase C are identical with that of the phase A; (3) a single-phase multi-feed interaction factor SMIIFij between the converter station i and the converter station j is calculated. By means of the method, references are provided for evaluating the strength of the interaction between all converter stations in the multi-feed direct current system in asymmetrical faults.