In the history of Chinese petroleum industry,the philosophical thinking is always used to guide practice. The Daqing Oilfield was developed based on the philosophical thoughts of Mao Zedong, i.e., On Practice and On Contradictions. Relying on the philosophical thoughts,the management and technology innovationsystem was continuously improved,and the technology management system with Daqing Oilfield characteristics was developed. This paper applies the thoughts of the "Two Theory" in oil production engineering,and analyzes the major challenges and countermeasures for the stable production of 4.0×107 to Daqing Oilfield. The scientific methodology of practice is used to guide the technical schemes and solutions. The "Two Theory" is proved to be effective to guarantee the stable production of 4.0×107 t.