In this paper, we develop a explosion-proof LED lighting (Ex circuit) circuit of Explosion-proof LED Signal Lamp (Ex LSL) to utilize the core module of the explosion-proof Local Control System (Ex LCS) for offshore plant applications. And then analyzed its electrical, optical and thermal characteristics. Ex circuit was applied input voltage from AC/DC(12~254) V. In this experiments, stable light-on characteristics were confirmed by eyes for the every input voltages with min. 78,462 and max. $517,975cd/m^2$ of luminance. also Output current and output luminance was made proportional. Because the measured maximum surface temperature of Ex circuit was $54.23^{circ}C$ at AC 48 V, Ex circuit was rated with T6 of temperature class. Finally, Ex circuit was shown stable light on characteristics under the $-50^{circ}C$ and $60^{circ}C$ during 12 hours of test period.