With the rapid development of urban rail transit in China, a large amount of muck is generated during shield tunneling, and its transportation and landfill will cause serious environmental issues. Based on the Suzhou Metro Line 8 section 6, full life cycle assessment method was used to analyze and compare the carbon emissions of conventional disposal and resource utilization of shield muck. Research results indicate that the total amount of muck produced during shield tunneling is 2.64 × 10⁵ m³ in this project. When traditional burial treatment is carried out for shield muck, the carbon emissions throughout its entire life cycle will reach 3.00 × 10⁶ carbon emission equivalents. In this case, 5.28 × 10⁴ m² of land with a 5-meter landfill depth will be occupied by shield muck. If shield muck and industry-byproducts are used for preparing synchronous grouting materials, the 28-day strength of the grouting material can reach 2.5 MPa. Grouting raw material cost by 467 thousand yuan/km will be reduced, and about 4.6 × 10⁵ carbon emission equivalents per kilometer will be reduced. The findings provide reference for optimizing the resource utilization of shield muck.