In this paper, a new control method based on combination of pulse-width modulation (PWM) and phase shift is applied to high voltage gain quasi-switched boost inverter (HG-qSBI), which enlarges its voltage gain and provides soft switching for its switches. Moreover, exploiting the proposed switching algorithm will add another parameter, phase shift value, to the voltage gain equation, which will increase flexibility of the inverter. In this paper, the steady-state analysis and design procedure are given. Then, the presented HG-qSBI with proposed switching algorithm is compared with other similar inverters to evaluate its capabilities. Finally, the simulation results in PSCAD/EMTDC software are given to validate the theoretical analysis.