Abstract: To ensure that power system transmission lines operate within health and safety protocols, a multilevel, multidimensional, assistant decision-making expert system based on an operation automation platform is proposed, and the project scheme design and application functions of the system are presented. The framework system is developed into subsystems of data processing, advanced applications, and information exhibition. This study analyzes key technical problems such as intelligent early warning, fault diagnosis, state evaluation, risk assessment, economic evaluation, multidimensional evaluation, and data processing. In addition, a hardware system and an instance using the proposed expert system are given. Results verify that this expert system can provide technical support for the safe running and operation decision making of transmission lines.