In practical applications of capacitive coupled non-contact voltage sensors, differences in wire diameter, insulation layer thickness, and the relative position between the wire core and the induction plate can affect the coupling capacitance between the wire core and the induction plate. Additionally, the presence of the wire influences the structural capacitance between the induction plate and the grounding plate, causing edge effects that alter the size of the structural capacitance. As a result, conventional LCR meters cannot accurately measure noncontact voltage, resulting in uncertain sensor gain and limited accuracy in noncontact voltage measurement. To address this issue, a non-contact voltage measurement method based on dual reference excitation signal parameter identification is proposed to achieve self-calibration of sensor gain during the measurement process. Firstly, an equivalent model with parasitic parameters is presented, and its transfer function is analyzed. Multiple internal parameters of the sensor are simplified into two lumped internal parameters. Through simulation, the influence of the measured wire on the edge effects of structural capacitance and its variation is revealed. Subsequently, a sensor parameter identification method is proposed to obtain the internal parameters of the sensor considering parasitic parameters and wire influences as a fixed parameter for voltage reconstruction to improve voltage measurement accuracy. A sensor prototype is developed, and an experimental platform is constructed to perform parameter identification and conduct multiple validation experiments. Experimental results show that the amplitude error in the amplitude accuracy test is within 1%, and the phase difference in the phase accuracy test is 0.13 °. The wire diameter adaptability experiment confirms that the method accommodates wires of different specifications, with a maximum error of only 0.15%. The interference signal shielding ability tests validate that the coaxial probe with a shielding cavity has good anti-interference performance. This provides an effective solution to improve the accuracy of non-contact voltage measurement.