The embodiment of the invention discloses a molten salt electrochemical multifunctional in-situ characterization device and a use method, and belongs to the technical field of high-temperature electrochemical analysis. The device provided by the invention can simultaneously support integration of in-situ Raman, in-situ optics and in-situ synchrotron radiation scanning, and can realize high-temperature melt structure analysis, in-situ visual display of the three-dimensional morphology of the electrode and deep and comprehensive understanding of the corresponding evolution process. The device is specifically composed of a vacuum heat preservation furnace body and a transparent electrolytic cell, and the vacuum heat preservation furnace body achieves three functions by designing a concave Raman corner objective lens inlet, an optical visualization window, a light supplementing window, an aluminum foil transmission window, a transparent quartz hearth, a two-section heating resistance wire and other systems. According to the transparent electrolytic bath, a furnace tube and a crucible of a conventional vertical resistance furnace are integrated, the crucible is connected with a rotating table at the bottom of a furnace body through machining, then the electrolytic bath rotates along with rotation of the rotating table in the testing process, and an electrode fault picture is obtained.