Using the Monte Carlo method, the energy losses in silicon carbide of heavy ions with different linear energy transfers (LETs) are simulated and calculated. The simulation results show that the energy loss per unit depth of heavy ions in silicon carbide is affected by both the ion energy and the incident depth. Primary heavy ions and secondary electrons mainly cause energy loss, and the non-ionization energy loss only accounts for about 1% of the total energy loss. With the increase of LET, the initial angle and energy distribution of the secondary electrons become more and more concentrated. The peak position of the generated charge deposition is in the center of the heavy-ion track, and the distribution is linearly decreasing in Gaussian form in the direction perpendicular to the incident depth. In the californium source experiment of SiC MOSFET, when the drain voltage is 480 V, the device has a single event burnout, and the breakdown voltage of SiC MOSFET is less than 1 V after burnout has occurred. With the experimental results, we carry out the TCAD simulation of SiC MOSFET and obtain the electric field distribution inside the device under different drain voltages. The electric field parameters are used in the Monte Carlo simulation of SiC MOSFET with considering the metal layer. It is found in the Monte Carlo simulation that the greater the electric field of the epitaxial layer, the longer the path of heavy ions moving on the epitaxial layer is and the more the deposited energy, and that the secondary electrons are more likely to move in the direction of the electric field as the electric field increases, resulting in excessive energy deposition in local areas.