The invention discloses a WPT optimal capacitance selection method based on single-circle circular PCB coils. The method comprises the steps of applying arbitrary capacitance to the PCB coils, calculating the parasitic capacitance of the coils through simulation, calculating the loss impedance of the coils according to the parasitic capacitance, the externally applied capacitance and the calculated self-inductance of the coils, and substituting the calculated loss resistance, parasitic capacitance, externally applied capacitance, self-inductance of the coils and the mutual inductance between the coils into an efficiency expression, thereby obtaining efficiency values under different externally applied capacitance values through calculation. Through the method, the frequency and capacitance value corresponding to the optimal efficiency can be obtained rapidly, thereby finishing the design.