Abstract: Investigation and research constitute the fundamental working methods of the Communist Party of China (CPC), as well as the CPC's fine tradition and ethos. MAO Zedong was not only an active advocate within the CPC for the vigorous promotion of investigation and research, but also an enthusiastic practitioner, forming a distinctive perspective and practice regarding investigation and research, which constituted an important component of MAO Zedong Thought. Entering a new era, the CPC once again vigorously promotes investigation and research. In the new era, in terms of ideological guidance, the mass line, problem orientation, and working methods, the legacy and development of MAO Zedong's ideas on investigation and research are inherited and advanced. Conducting an in-depth analysis and exploration of the continuous connection between the two can deepen our understanding of the CPC's ideas on investigation and research. It can also aid in better comprehending the fundamental requirement of 'vigorously promoting investigation and research throughout the entire Party' and in effectively applying the principles of XI Jinping's Socialism with Chinese Characteristics for a New Era.