Abstract: As emerging market entities, the virtual power plants have gradually gained their access statuses in the multi-market trading varieties. They have expanded the adjustable resources for the new power systems by aggregating the flexible distributed resources in response to the system dispatching instructions and the executing transaction results. At present, the virtual power plants are in a business form of trading in the auxiliary service market supplemented by taking part in the energy market. With the penetration of a high proportion of renewable energy, the transition of virtual power plants to the spot market will become an important business development direction. This paper studies the spot market clearing model adapted to the participation of the virtual power plants, allowing the virtual power plants to reflect their own flexible regulatable characteristics by introducing the flexible bidding ways to improve the matching rate of supply and demand in the electricity market transactions. At the same time, this paper proposes a premium evaluation for the flexibility of virtual power plants based on the comparison and analysis of the clearing results of different transaction models, which realizes the pricing system transformation from energy only to "energy + flexibility" two-part tariff and improves the competitiveness and value certification of the virtual power plants in the electricity market.