A basic single-phase SPWM inverter of proportion control is studied in this paper. First, a one-dimension discrete model of sine inverter is established. Then stroboscopic sampling diagram, folded diagram and sampling bifurcation diagram are used to describe the bifurcation and chaos phenomena, and steady parameter area is derived by simulation. Lastly, the impact on system performance by bifurcation and chaos behavior is analyzed from the perspective of time domain and frequency domain. The study expands the chaos researches from DC/DC converters to DC/AC converters, and lay the foundation for the deep study of nonlinear dynamics in power electronics.