The invention relates to a device for removing gaseous tritium and isotopes thereof in a molten salt. The device comprises a fused salt loop and a separation assembly connected with each other, wherein the fused salt loop comprises a molten salt reactor core; the molten salt serving as a coolant flows through the molten salt reactor core and carries gaseous tritium and isotopes thereof to flow in the fused salt loop; the separation assembly comprises a palladium tube and a stainless steel housing; a molten salt inlet/outlet is formed in the palladium tube; the molten salt enters or flows out of the palladium tube via the molten salt inlet/outlet; a purge gas inlet/outlet is formed in the shell; purge gas enters or flows out of the shell via the purge gas inlet/outlet; the purge gas flows between the outer surface of the palladium tube and the inner surface of the shell and carries out the gaseous tritium and isotopes thereof which diffuse from the molten salt and penetrate through the palladium tube. The invention further provides a method for removing gaseous tritium and isotopes thereof in the molten salt. According to the device and method for removing gaseous tritium and isotopes thereof in the molten salt disclosed by the invention, the palladium tube serves as a core component, so that the gaseous tritium can be separated and removed.