The mechanism of dead-time effect is illustrated, as well as its influences on fundamental output voltage and harmonic spectrum distribution. Combining the basic analysis and the bandwidth of the system close loop transfer function, the suppression effect on dead-time and the close relationship between the close-loop bandwidth and the suppression effect are quantitatively analyzed. Taking the single loop controlled LCL inverter as an example, the suppression effect of the close-loop control bandwidth on dead-time is verified by simulation. Finally, experiments are performed on a 250 kW grid-tied inverter to check the suppression effect on dead-time. Simulation and experimental results agree well with the theoretical analysis.