The corrosion behavior of Haynes H214 alloy in a KCl–MgCl2 molten salt at 700 ℃ was investigated through corrosion rate tests and analysis of the corrosion product phases and morphologies. Results indicate that the corrosion rate of H214 alloy in KCl–MgCl2 at 700 ℃ occurs in two stages. For corrosion times of  ≤48 h, the overall corrosion rate is relatively low and increases in a parabolic manner. For corrosion times between 96 and 240 h, the corrosion rate significantly increases and follows a linear relationship. The alloy undergoes uniform corrosion in the molten salt, with the corrosion products mainly consisting of Al, Mg, and O-rich compounds interacting with the residual Ni matrix. As the corrosion time extends, the outer layer of corrosion products tends to spall off, and the thickness of the corrosion products increases approximately in a linear relationship. The corrosion reaction is consistent with the “activation oxidation” theory. During the reaction process, Cl2 and low-melting-point eutectics are formed, which have strong volatility at high temperatures. This leads to the formation of porous and loose corrosion products that do not provide effective protection for the metallic substrate.