Against the backdrop of the "Dual Carbon" goals and energy transition, the coal industry is accelerating its transformation toward green, intelligent, and efficient development. Taking Qianjiaying Coal Preparation Plant of Kailuan Group as a research example, this paper systematically explores the modernization path of large coking coal preparation plants from the dimension of engineering design. Aiming at the pain points of the original plant, such as outdated processes and lagging efficiency, core technologies including intelligent dry separation, pressureless three-product heavy-medium cyclone separation, deep coal slime flotation, high-efficiency solid-liquid separation, and high-precision online detection are applied to construct an integrated process system of "intelligent perception-precise separation-efficient recovery". Meanwhile, an intelligent management and control platform is established, integrating 5G, big data, and artificial intelligence technologies to achieve full-process automatic control of production and real-time monitoring and analysis of data.In terms of green development, energy consumption is reduced by optimizing transportation and storage systems, and facilities for dust removal and purification, washing water recycling, and comprehensive solid waste utilization are deployed to integrate green and safety concepts throughout the construction and operation processes. This practice has achieved dual breakthroughs in economic and ecological benefits, providing replicable practical experience for the coordinated development of the coal industry and the ecological environment, and indicating the direction for the transformation and upgrading of similar coal preparation plants.