In this study, a novel split gate trench MOSFET with a high-k pillar (HKP SGT-MOS) embedded is proposed. Lots of electric displacement lines are allowed to enter into high-k pillar introduced beneath split gate, thus relieving the crowding of electric field at bottom corner. Therefore, the HKP SGT-MOS can achieve a higher breakdown voltage(BV) without sacrificing its forward conduction. Various dielectrics for the high-k pillar, including SiO2, Si3N4, Al2O3 and HfO2, are investigated and the results reveal that HfO2 has the largest FOM and BV. The characteristics of HKP SGT-MOS have also been validated by TCAD simulation, and it is shown that the BV and figure of merit (FOM=BV2/Ron,sp) are 258.3V and 37.46 MW/cm2, achieving 36.7% and 87.02% improvement compared to the conventional SGT-MOS, 18.4% and 38.59% improvement compared to the SGT-MOS with short split-gate. Moreover, the influences of drift doping concentration, mesa width, length and width of split gate/high-k pillar are also studied to optimize the HKP SGT-MOS.