The invention discloses a high-temperature fused salt electrochemistry in-situ synchronous radiation studying device which comprises a vacuum furnace, a fused salt tank, a heating device, a baffle arranged at the opening of the vacuum furnace and a three-electrode system. A cavity is formed in the vacuum furnace which comprises a furnace body, an opening is formed in the top of the furnace body, an incidence window, a transmission window and a fluorescence window are formed in the wall of the furnace body, the incidence window and the transmission window are in coaxially collinear arrangement, and axis of the fluorescence window and that of the incidence window are positioned on a same horizontal plane; the fused salt tank and the heating device are arranged in the cavity of the vacuum furnace, the three-electrode system is used for providing electrochemical reaction for a system in the fused salt tank, and three electrodes are connected with an electrochemistry workstation through leads. By adopting the device, electrochemical reaction at high temperature can be realized, and substance change in the electrochemical process can be detected by means of fluorescent detection.