The invention provides a 3D printed cobalt-chromium alloy for dental porcelain repair and a preparation method thereof, and belongs to the field of dental porcelain repair. A Ta element is added, so that the thermal expansion coefficient is reduced, the metal ceramic bonding strength is improved, the surface active energy is reduced, solid solution strengthening is caused, and the strength is improved; the content of a Cr element is increased, the content of a Co element is reduced, the content of a hcp phase is increased, metal and ceramic bonding is facilitated, after the content of the Co element is reduced, combination of Cr-W, Cr-Mo, Cr-Si and W-Mo is improved, and the strength of the alloy is improved; vacuum stress relief annealing is adopted, and residual stress is completely eliminated, so that microstructure phase change caused by the residual stress in the service process of a cobalt-chromium restoration is avoided, and micro-cracks are prevented from being formed on a metal-ceramic bonding interface; and solid solution and aging are adopted, the composition of a cobalt-chromium alloy phase and precipitation of a second phase are adjusted, so that the alloy has good mechanical properties, meanwhile, the hcp phase is further improved, and the metal-ceramic bonding strength is improved.