This paper researches on nonlinear phenomena in H-bridge inverter using current loop proportional control. Stroboscopic map is adopted to build discrete model of the inverter system. The system dynamic bifurcation diagram is obtained according to input voltage E, proportional coefficient K and load resistance R as bifurcation parameter respectively. Folded diagram is used to analysis process from stability to chaos with E, K, R change respectively. Influences on system dynamic performance caused by bifurcation parameters are studied using bifurcation diagram, folding graph and Jacobian matrix. Spatial stereogram of E, K, R is used to show stable region of the system. Time domain waveform of output current is achieved based on Matlab/Simulink. The simulation results are consistent with theoretical analysis results which reveal the validity of the proposed discrete model and theoretical analysis.