Abstract: Based on the technical indicators of the construction clearance and inner lining profile for single-tube double-track high-speed railway tunnels with design speeds of 300-350 km/h, a design method for segmenting prefabricated assembled secondary lining blocks in drill and blast tunnels is analyzed and proposed. Calculation formulas for determining the geometric parameters of prefabricated assembled secondary lining blocks are presented and verified with examples. Additionally, the assembly methods of prefabricated secondary lining blocks with straight joint and staggered joint high-speed railway tunnels are proposed.