The reform and opening-up initiative has left us with many valuable historical lessons. This paper mainly discusses the historical background of reform and opening-up, Deng Xiaoping Theory, historical lessons, and explores the reform and opening-up in the new era, in light of the decisions made at the Third Plenary Session of the 20th CPC Central Committee. Comprehensive deepening of reform in the new era must adhere to the principle of upholding the Party's overall leadership and the people-centered approach. While focusing on promoting economic system reform, it is essential to coordinate and plan reforms in other fields to fully advance the great rejuvenation of the Chinese nation through Chinese-style modernization.