With the twin threats of warming climate and energy shortage, achieving the dual carbon goal has become a global urgent task, and promoting enterprise energy transition, especially for the oil companies. Multi-energy complementary technology facilitates the comprehensive utilization of distributed and renewable energy, acting as a cornerstone for corporate energy transition. This approach is significant for increasing the penetration of renewable energy and improving overall energy efficiency. This paper begins by elucidating the background and significance of multi-energy complementarity. It then provides an overview of multi-energy complementary systems, covering their definition, operational models, and related policies. Subsequently, the paper details the key technologies and evaluation metrics for multi-energy complementary development, with a focus on planning and design, coordinated control, energy management, and energy storage technologies. Finally, the paper identifies current challenges in multi-energy complementary development and discusses future trends.