Investigation of electrocatalytic reactions and processes at molecule level is of essential importance in the successful development of electrocatalyst. It is critical to understand the detail pathways and mechanism of complex electrocatalytic processes in order to control the reaction and suppress the formation of byproducts. Based on its fingerprint and surface selection rules, electrochemical in-situ FTIR spectroscopy (in-situ FTIRS) is a powerful method to acquire real-time information about the chemical nature of adsorbates and the solution species involved in electrochemical reactions. These unique features make this technique well-suitable and widely applicable in electrocatalytic reactions. In this paper, we review recent progresses of in-situ FTIRS and its application in the investigation of electrocatalytic reactions and processes. First, we focus on the in-situ FTIR studies of electrocatalytic oxidation of small organic molecules. Next, in-situ FTIR characterization of electrocatalysts through employing a probe molecule, i.e. CO, is reviewed. Finally, the application of in-situ FTIRS to analyze some important electrochemical processes such as CO2 electroreduction, biomolecule reaction and Lithium ion battery is reviewed. The body of work has advanced the knowledge of electrode process and summarized the frontier in study of electrocatalytic reactions and processes at molecular level.