This studyfocuseson designing and optimizing a1000V verticaldouble-diffusion metal oxide semiconductor (VDMOS) field-effect transistor using 4H-SiC. Leveraging Silvaco simulation software ,we comprehensively investigate the relationship between device parameters and withstand voltage characteristics ,aiming for a 50% margin. Following optimization ,the device achieves a threshold voltage of 2. 3 V ,with the breakdown voltage reaching 1 525 V. Compared with an Si-basedVDMOS underidenticalwithstand voltageconditions ,the breakdown voltage of the 4H-SiC VDMOS increases by12%. Notably ,the surface electric fielddistribution of the4H-SiC VDMOSduringbreakdown remainsrelatively uniform ,with a maximum value of3. 4× 106 V/cm. The effective terminal length measures at 15 μm ,approximately 6% that of an Si- basedVDMOS ,with the overall area reducing by nearly 1/10. Furthermore ,the structure is simpler compared to thatofthe4H-SiC VDMOS underidenticalwithstand voltage conditions. It involves no additionalprocess steps ,thus facilitating easy device fabrication.