The invention discloses an electric power system stability evaluation method including a complex electric-power device model. The method efficiently calculates effects of a complex electric power device on a jacobian matrix in stability evaluation calculation through an automatic differential technology and through design of partial automatic differential and decoupling automatic differential policies, defects of poor calculation efficiency of a traditional automatic differential technology are overcome so that effective balance between code maintainability and code efficiency is obtained. The method is capable of meeting demands on complex electric-power device model processing in stability evaluation of a large-scale electric power system and applicable to the field of analysis, operation and control and the like of a modern electric power system.