An optical fiber communication system based on ring topology is proposed for the development of subsea oil and gas fields reconnecting to the existing facilities with limited resources reserved fiber cores， which is based on the efficient utilization rate of optical fiber resources and the superior scalability of topology based on ring topology， and only 4-core fibers are needed for a single loop， which can effectively solve the problem of limited optical fiber resources， and the system has superior expansion ability. Then， the scheme design of the system is carried out， and the standards and methods of the communication verification and practical application case are given， Finally， based on the characteristics of different projects of the subsea production system， the applicability of the star topology and the ring topology is analyzed， which provides a reference for the communication scheme design of the subsea production system.