With the increasing growth of renewable energy sources, their decentralized, intermittent, and volatile characteristics have become prominent challenges. To address these issues, a novel solution called the virtual power plant （VPP） has been proposed. Firstly an overview of VPPs is introduced, the current research status is analyzed from three perspectives: coordinated control technology, optimal scheduling, and market trading. Furthermore, different models and algorithms for optimal scheduling and their advantages and disadvantages are analyzed. The paper also highlights the benefits of blockchain technology in distributed trading and discusses the feasibility of applying blockchain to VPP trading. Finally, future research directions in the field of virtual power plants are prospected.