Abstract: Aiming at the problem of frequent production interruptions caused by insufficient reliability, poor real-time performance, and bandwidth limitation in the industrial control network of coal washing plant in coal mine, a robustness optimization scheme based on industrial fiber optic ring network is proposed. A 50 ms level link switching is achieved through a dual fiber three routing topology and G.8032 ERPS protocol, a network security protection system is constructed combined with AES-256 encryption, two-factor authentication, and parallel redundancy protocol (PRP); Through OTDR precise positioning and intelligent operation and maintenance system, the entire process closed-loop management from fault perception to repair is achieved. The application of coal washing plant in Daizhuang Coal Industry shows that the network availability is improved from 99.2% to 99.95%, the average repair time is shortened by 67% to 1.5 hours, and the annual failure rate is decreased from 12 times to 2 times (with a reduction of 82%). This scheme provides reliable guarantees for the efficient and safe production of coal washing plants in coal mines, at the same time, provides reference for the construction of network infrastructure for Industry 4.0.