A high-frequency half-wave rectifier system of low-harmonicity and high-efficiency, which mainly comprises: a current output device having an output end and a first flow-return end respectively at both ends, a rectifying module, a resonant tuning unit, a first node, a voltage regulator module, at least one load element, a grounding portion, and at least one flow-return path. By means of the above structure, a simple circuit configuration and appropriate capacitance value setting are used to control the duty cycle of the rectifying module to approximately 74 nanoseconds and adjust the output power and improve the AC to DC conversion efficiency for the rectifying module under the low electromagnetic interference condition.