The concept of hybrid switch(HyS) by paralleling low-switching-loss silicon carbide(SiC) MOSFETs and low-cost silicon(Si) IGBTs offers an improved performance and cost tradeoff in motor control unit(MCU) for electric vehicles(EVs). In this paper, the loss and thermal models are developed for the proposed HyS. Based on that, a multi-objective method is proposed to select the optimal ratio for the HyS. Reliability of Hybrid Switch for EVs under active short circuit(ASC) operating condition is verified by Simulation. Furthermore, both EV model is developed to evaluate the performance/cost of HyS with endurance mileage under China light-duty vehicle test cycle(CLTC) profile. Several challenges of developing HyS are also discussed. It is found that the combination of 1 SiC MOSFET and 3 IGBTs and DIODEs is the low-cost scheme with optimized junction temperatures, while the scheme with 2 SiC MOSFETs and 2 IGBT and DIODEs is the one with the highest efficiency. The HyS with the high-efficiency ratio has a 4.7% increase in endurance mileage compared with IGBT.