<p>The mobile welding robot (MWR) embodies remarkable versatility, distinguished by its agile manoeuvrability and robust environmental adaptability. It excels in executing automated welding tasks under special conditions, including intricate spatial surfaces, unconventional cross-sections, confined spaces, and even underwater and nuclear environments. However, the current research landscape of MWRs, both domestically and internationally, is characterized by disorganization, irregularity, and a lack of systematicity, resulting in a failure to provide comprehensive and insightful references for studying MWRs across diverse scenarios. This paper conducts a thorough review of the existing research on MWRs within diverse specialized industrial operating contexts, both locally and globally. This underscores the urgent need to establish a modular standard for MWRs and develop a robust configuration design system, which can serve as a valuable reference. On the basis of this foundation, this paper meticulously examines the critical technical challenges encountered in the application of MWRs. Ultimately, it offers an outline for the future development trajectories of MWR technology, aiming to serve as a valuable resource and guide researchers embarking on investigations into MWRs under exceptional operating conditions.</p>