Since General Secretary Xi Jinping put forward "the formation of a new development pattern with domestic and international dual cycles as the main body and mutual promotion of domestic and international dual cycles", "dual cycles" have become a hot issue. The studies show that:1) The US-China economic and trade frictions overlapped with the global spread of COVID-19 have caused China's economic and trade development to encounter a "quadruple dilemma", namely, peer-to-peer countermeasures, pandemic shock, lack of trust, and political frictions. The new development pattern, which promotes the mutual promotion of domestic and international dual cycles, is a new era strategy to break through the "four dilemmas". 2) The relatively limited domestic effective demand in China determines the more need to promote the domestic and international dual cycles to achieve real mutual promotion. The ineffective supply of some domestic products and the insufficient effective supply of some high-end products determine that China needs to actively expand effective market demand and effective product supply under the pandemic. 3) We need adhere to the market-oriented allocation of factors and optimize the business environment, so as to make the market intersection of domestic and international dual-cycle mutual development bigger and stronger. 4) It is necessary to adopt multi-policy measures, such as building a dual-cycle overseas hub, supporting central city radiation, and implementing regional gradient complementary strategy, etc., to coordinate the promotion of full opening up, and to accelerate the formation of a large market with market-oriented allocation of factors, mutual promotion of domestic and international dual cycles, and orderly competition and integration to support sustainable economic growth in China.