Abstract: Stability control of newly excavated roadways in layered backfill is critical to ensuring safe underground mining operations. Taking a phosphate mine in Guizhou Province,as the engineering background,this study introduced the Coal Mine Roof Rating(CMRR) method and employed a comprehensive research approach combining field investigation,laboratory testing,and theoretical analysis to evaluate the roof quality grades of newly excavated roadways within layered backfill,and to assess the applicability of the CMRR method to backfill mining in phosphate mines. Based on the rating results and onsite conditions,the roadway support scheme was optimized. Numerical simulations were conducted to compare and analyze,before and after support optimization,the displacement distribution of the roadway roof,support structure displacements,plastic zone distribution,and dissipated energy density characteristics. Field industrial trials were carried out,and roof separation monitoring data over 69 days were obtained to validate the numerical simulation results. The findings indicate that the CMRR ratings for the two monitoring points in the newly excavated roadway within the backfill correspond to a moderate roof and a weak roof,respectively. The optimized support scheme significantly improved roadway stability:the maximum roof settlement and horizontal displacement were both reduced by 80%,bolt displacement decreased by 79. 6%,the extent of the plastic zone shrank by 52. 2%,and the dissipated energy density dropped by 91. 5%. These results confirm the applicability of the CMRR method for quality evaluation of layered backfill masses and provide both theoretical and practical references for innovating stability control technologies for newly excavated roadways in such backfill environments.