Abstract: Addressing significant deformation in the surrounding rock of deep soft rock road-ways subjected to repetitive repairs, this study focuses on the 21st transportation downhill of Quandian coal mine as the engineering context. We propose the variable-diameter partition roadway pressure relief technology. This approach utilizes theoretical analysis, numerical simulation, and practical engineering methods. We established a theoretical model for pressure relief parameters, derived essential parameters for pressure relief, and outlined the distribution pattern of elastic strain energy density. Additionally, we uncovered the principles governing energy dissipation in borehole unloading, ultimately determining the optimal value for key pressure relief parameters. The study findings indicate the following: ① The variable-diameter zoned pressure relief technology enlarges the energy reduction zone near the roadway while diminishing the energy elevation zone in the roof and floor. It redirects concentrated energy from the shoulder and floor corners deeper into the area, achieving precise pressure relief control within the roadway. ② Increasing the length of shallow small-diameter boreholes (L₁), the length of deep large-diameter boreholes (L₂), and the radius of deep large-diameter boreholes (r) corresponds to increasing pre-peak, post-peak, and post-peak values in the elastic strain energy density curves, demonstrating an overall positive correlation. ③ As the spacing (D) of deep large-diameter boreholes increases, the peak value of elastic strain energy density between holes shows the characteristics of firstly increasing, then decreasing and then stabilizing, and the effect of unloading joint pressure between boreholes is negatively correlated with it, and based on the magnitude of the increase in the peak value of elastic strain energy, the key parameters affecting the effect of unloading are weighted as follows in the order of: L₁, L₂, r and D. ④ Based on the theoretical analysis and numerical simulation to determine the key parameters of the 21st transportation downhill roadway pressure relief technology reasonable value, roadway implementation of variable-diameter zoned pressure relief technology, the two ribs and the roof and floor deformation were reduced by 58.7%, 23.7%, and 27.4%, respectively, the stability of the roadway has been effectively controlled, confirming the effectiveness of the variable-diameter zoned pressure relief technology.