The invention discloses an MZ type optical waveguide electric control depolarizer. The invention comprises an input straight waveguide, a 1:2 beam splitting waveguide, a modulation electrode, a 90-degree polarization rotation waveguide, a straight waveguide, a curved extended-range waveguide, a 2:1 beam combining waveguide and an output straight waveguide; wide-spectrum TE polarized light is inputfrom the straight waveguide, and is split into two beams of wide-spectrum TE polarized light after passing through the 1:2 beam splitting waveguide, the wide-spectrum TE polarized light of the upperbranch of the 1:2 beam splitting waveguide is converted into the wide-spectrum TM polarized light after passing through the 90-degree polarization rotation waveguide, the wide-spectrum TM polarized light enters the upper branch of the 2:1 beam combining waveguide from the straight waveguide, the lower branch of the wide-spectrum TE polarized light passes through the curved extended-range waveguideand then is converged with the upper branch of the wide-spectrum TM polarized light in the output straight waveguide to form depolarized light. According to the invention, the modulation electrode realizes the precise adjustment of the light splitting ratio of the two arms through electric control, and the TE and TM energies in the output straight waveguide are equal to each other; and the MZ type optical waveguide electric control depolarizer overcomes the light splitting unevenness caused by the loss of the polarization rotation waveguide and the transmission loss of the TE and TM waveguides.