The nuclear safety-class digital control system (DCS) is crucial for the safe operation of nuclear power plants, performing critical functions such as emergency trip. With the advancement of multi-unit nuclear power plant construction, achieving “multi-reactor reuse” of safety-class DCS has become a core requirement. The traditional single-unit independent design model leads to long cycles, low reusability, and high human error risks. To address this, this study proposes a standardization optimization strategy, at the design specification level, restructure variable identification standards, unify variable naming and logical layout, standardize signal auxiliary interfaces, and establish human error prevention identification standards, to enhance the compatibility and consistency of instrumentation and control function diagrams and electrical designs across multiple units; at the design tool level, develop a dedicated migration tool to support automated migration of design documents, drawings, and code packages, as well as batch modification of reactor identification information, improving reuse efficiency; at the electronic data archiving level, optimize archiving methods to enhance data reusability. This strategy effectively reduces design redundancy and reduces human error risks, providing an efficient and reliable DCS technical support for multi-unit nuclear power projects. This study will conduct a systematic analysis and practical verification of this strategy.