This study aims to analyze and visualize the research hotspots, evolution, and emerging trends of blended learning in a holistic way. In this study, 1657 biblio-metric records together with 48310 citations are collected from SCIE, SSCI and A&HCI databases. CiteSpace is adopted in the analysis and visualization. Results show: enhancing collaborative learning, pattern, and teacher training are the re-search hotspots in Period I, instructor perception, possible future direction, and research trend are the research hotspots in Period II, general science classroom, blended learning environment, and measuring student engagement are the re-search hotspots in Period III; the themes of covid-19 remain similar along the de-velopment, while the themes of digital health education change a lot; blended learning environment, online component, covid-19 pandemic, procrastinating be-havior, active blended learning, and observed learning orientation are the emerg-ing trends. These findings could provide research directions for future studies in blended learning.