A mathematical model for calculating the current dependent melting temperature of linear fuse wire is setup to deal with the high-voltage current-limiting fuse. The key point is that it can accurately calculate the tempera-ture of the fuse under low current ratio. A 3D thermal-electric coupling model is set up to simulate the heating pro-cess of the fuse element by using the software Ansys

and the obtained temperature melting time of the fuse are com-pared with the measured data to verify the high accuracy of the model. This model and the method may provide a theo-retical reference for engineering applications.