Microwave wireless power transfer (MWPT) can realize long-range power transmission compared with other wireless power transfer techniques. The traditional MWPT system is based on a continuous power supply structure. When the load power demand changes, the transmission power should be reduced to achieve power balance. Therefore, the power amplifier (PA) and rectifier circuit in the system are sensitive to the input power level and would suffer from low efficiency when input power varies. As a result, the system efficiency decreases significantly in a wide power range. To address this issue, an impulsive MWPT system structure using power amplitude and pulse width modulation (PAPWM) is proposed in this paper. Through the power amplitude modulation (PAM) and power pulse width modulation (PPWM) of the PA, the efficiency optimization and power balance of the system can be respectively achieved in the wide power range. A 5.8-GHz/30-W MWPT system prototype is fabricated and tested in the laboratory, and experimental results are provided to verify the effectiveness of PAPWM in improving the efficiency int the wide power range.