The width of production drifts has a definitely significant effect on the economic benefits of mines adopting sub-level caving mining operations. In this study, an optimization method has been presented to determine the width of production drifts in sub-level mining, based on the stability analysis of pillar between sub-level drifts using the stochastic medium theory for ore draw, Wilson theory and FLAC3D routine. The case study of an iron mine in Xinjiang, China, shows that the theoretically optimal width for the drifts is 7 m, and this figure is optimized to 6.6 m after a detailed technological and economical investigation of seven various drift widths has been made by using the highest integral method. The optimization results indicate that the effect of ore drawing is good, and the profit for a single drift is increased by 0.6 million Yuan accordingly. This methodology present involves an integrated consideration of safety, practices for driving and supporting drifts and economic benefits in sub-level caving mining, and can be of significance to guide production operations for similar mines.