As a model reaction for the electrooxidation of many small organic molecules, formic acid electrooxidation (FAEO) has aroused wide concern. The promises of direct formic acid fuel cells (DFAFC) in application further strengthen people’s attention to the related research. However, despite decades of study, the FAEO mechanism is still under debate due to the multi-electron and multi-pathway nature of the catalytic process. In this review, the progresses towards understanding the FAEO mechanism along with the developed methodology (electrochemistry, in-situ spectroscopy, and theoretical calculation and simulation) are summarized. We especially focused on the construction of anti-poisoning catalysts system based on understanding of the catalytic mechanism, with anti-poisoning catalyst design being systemically summarized. Finally, we provide a brief summarization for current challenges and future prospects towards FAEO study.