Three-phase Split-source inverter (SSI) has recently been proposed as an alternative to the three-phase Z-source inverters (ZSI). This paper introduced an improved finite control set-model predictive control (FCS-MPC) algorithm for the SSI. The proposed FCS-MPC algorithm reduces the computational burden by selecting the discharging vector directly according to the current status of the inductor compared to its reference point instead of checking the other states. Moreover, it simplifies the cost function by removing the inductor’s current term, and thus no weighting factor is needed inside the cost function. A detailed analysis of the proposed algorithm is presented in this paper. Finally, simulation results based on MATLAB have been introduced to show the viability of the presented research and theoretical study of the FCS-MPC algorithm of the three-phase SSI under different operating conditions.