The invention discloses a spring cluster type thrust bearing mirror plate horizontal adjustment method. The spring cluster type thrust bearing mirror plate horizontal adjustment method comprises the following steps that step 1, the flatness of a thrust pad installation position on thrust bearing seats is measured; step 2, the thickness of each point of thrust pads is measured; step 3, the size ofadjustment steel pads corresponding to each thrust pad is calculated; step 4, the adjustment steel pads are arranged on the thrust bearing seats; step 5, a plurality of springs are arranged on the adjusting steel pads; step 6, the thrust pads are installed above the springs, and the thrust pads are fixed to the thrust bearing seats; and step 7, annular mirror plates are arranged above the thrust pads. The size of the adjustment steel pads calculated by each size can reduce the flatness difference between the thrust pads, and the flatness of the mirror plates is improved.