Abstract: Provided is a pier scour protection method by combinating a downward bivariate normal distribution surface and a granular mixture, wherein the method is used for protecting a pier foundation of a sea-crossing or river-crossing bridge from scouring, and when a depth of a local scour hole around the bottom of a pier or a bridge pile reaches a set depth, a downward bivariate normal distribution surface protection structure is laid, and the granular mixture with a specific thickness is laid in the downward bivariate normal distribution surface protection structure. A downward bivariate normal distribution surface structure for defending and a granular mixture layer for weakening horseshoe-shaped vortexes in a scour hole are organically combined, the bivariate normal distribution surface structure is mainly used for defending the downflow in front of the pier, and the granular mixture layer can weaken the horseshoe-shaped vortexes around the piers.