Previously, offsets between galaxies and mass during cluster collisions were regarded as a promising indicator for evaluating the self-interaction cross-section of dark matter. However, past investigations based on these offsets have been hindered by significant biases regarding the phase and geometry of the merger. I will introduce a reliable constraint on the self-interaction of dark matter using a novel and effective approach with observations of cluster collisions featuring double radio relics. By utilizing the distance between relics relative to the distance between halos as a gauge for dark matter characteristics, we have established an upper limit of 0.33 cm^2 g^-1 for the self-interaction cross-section with 68% confidence. This marks the first robust outcome derived from colliding clusters, accounting for ambiguities such as mass variability, viewing angle, collision velocity, merger phase, impact parameter, and gas slope.