Abstract: Under the development wave of Industry 4.0, industrial Passive Optical Network (PON), characterized by its high bandwidth, low latency, high reliability, and strong anti-interference capability, has demonstrated significant potential in the Industrial Internet sector. The deep integration of Industrial PON and Industrial Internet has become an unstoppable trend, jointly driving the manufacturing industry towards high-end and intelligent development. This article outlines the fundamental concepts and related technologies of Industrial PON and Industrial Internet, analyzes the key technologies and developmental challenges faced by the network connectivity layer of Industrial Internet, and focuses on exploring the integrated application of Industrial PON within Industrial Internet, particularly in smart factories. This integration aids the industrial sector in achieving digital transformation and upgrading, providing a reference for promoting the synergistic development of both technologies. Furthermore, the article provides an outlook on slicing technology and 50G PON technology within Industrial PON, specifically researching the challenges facing the future development of 50G PON. The aim is to offer references for advancing the sustained development of Industrial PON in the industrial field.