Problems exist in blasting excavation of Grade Ⅳ and Ⅴ surrounding rocks of single-track railway tunnel by conventional micro-bench method. Hence, the problems of conventional micro-bench method are summarized; the basic principles for bench size are proposed by investigation and theoretical analysis; a stable precise blasting design system for micro bench maintenance is established; a kind of W-shaped blasting network and a retractable lightweight operational platform with sliding device are developed; and a series of new excavation technology of one-time blasting of micro-bench with invert is obtained. The applicable results of the recommended technology to Youyi Tunnel on China-Laos Railway show that the new construction technology of micro-bench blasting excavation with invert can not only avoid the shortcomings of conventional one, but also greatly improve the standardized management level and project progress to realize normalized construction management.