To conduct a visualization analysis of the current research status, hotspots, and emerging trends in the literature related to the application of functional near-infrared spectroscopy (fNIRS) in the field of autism spectrum disorder (ASD). Methods: Relevant articles on the application of fNIRS in the field of ASD up to April 2024 were retrieved from the Web of Science Core Collection database. CiteSpace 6.3.R2 was used for visualization analysis to create knowledge maps, including co-occurrence and burst maps of authors, institutions, countries, and keywords. Results: A total of 179 articles were included. The annual publication volume showed an overall fluctuating upward trend. The author with the highest publication volume was Li Jun, the institution with the most publications was South China Normal University, and the country with the highest publication volume was the United States. Hot keywords included children, activation, brain, functional connectivity, cortex, etc. The keyword burst analysis revealed that early research in this field focused on brain function studies in typically and atypically developing children, followed by further confirmation of abnormal interhemispheric connectivity and coordination patterns in ASD. More recent research has focused on exploring differences in brain region activation and functional connectivity between ASD children and typically developing children, as well as integrating various classification algorithms with brain-computer interface technology. Conclusion: The popularity of research on the application of fNIRS in the field of ASD is generally increasing.