Owing to the continuous advancement of power-system intelligence, new power systems have imposed higher requirements for intelligent power-sensing technology. The current SOI platform of the MZI-type electric-field sensor features a narrow linear operating range, low sensitivity, and other issues. Hence, in this study, we proposed using the non-resonant state of the phase response of the microring to compensate for the MZI third-order cross-modulation distortion solution. Additionally, we performed a theoretical analysis of the different structures of the microring-assisted MZI and the use of the Lumerical software for structural simulation to verify the feasibility of the improved microring. Ultimately, we proposed the combination of two types of typical electro-optic polymers to complete the preparation of the electric-field sensor. The results of input–output testing and AC response tests of the prepared electric-field sensor show that the linear range of the slit runway-type microring-assisted MZI electric-field sensor improves by 77% and that the sensitivity of the electro-optic polymer with a high electro-optic coefficient can reach up to 1.034 mV/(kV/m), which is 2.9 times higher than that afforded by an unimproved sensor. Good responses are indicated in the AC response test. Research methods, such as theoretical analysis, simulation models, and experimental tests, confirm that the optimization strategy adopted in this study effectively improves the performance of the sensor and provides a reference for improving the direction of the topological structure of SOI optical electric-field sensors.