Through derivation and analysis on mathematical model of the temperature rise process of fuse melt under 8/20 μs lightning current, it is considered that the thermal conductivity of melt material, the normal temperature resistivity, the ambient temperature and the abnormal fracture of melt may affect the temperature rise process of fuse melt and then affect its working performance. On the basis of reasonably simplifying the melt structure of a fuse and putting forward relevant assumptions according to the actual situation, the melt thermoelectric coupling finite element model is established by using ANSYS, and the temperature rise of normal melt and melt affected by the above four factors under different lightning current amplitudes is simulated. The characteristic curves of lightning current amplitude-pre arc time of fuse are obtained. It is shown that these four factors will affect the melt temperature rise speed under the action of lightning current, and then affect the melt temperature rise process and the fuse pre arc time, which may cause the fuse to melt and reduce the working performance. Finally, through the comparison of simulation results, four measures to ensure the safe and normal operation of fuse are put forward.