The invention discloses an optimal optical offset point selecting method for preparing an integrated common-path interference electric field sensor, and belongs to the technical field of the optical electric field sensor. According to the method, firstly N parallel optical waveguides having different pre-diffusion width are arranged on a chip unit required for manufacturing the integrated common-path interference electric field sensor according to the distribution curve of the static offset point along with the optical wavelength and the optical waveguide pre-diffusion width, and M optical waves having different wavelength are selected in the commonly used light source band; then the pre-diffusion width values of the N set optical waveguides and the wavelength values of the M selected optical waves are multiplied in pairs to be combined, the optical offset point closest to 90 degrees is selected to acting as the optimal optical offset point and the optical waveguide of the optimal optical offset point is determined; and finally the integrated common-path interference electric field sensor is manufactured according to the selected optical waveguide having the optimal optical offsetpoint on the chip unit.