The present disclosure relates to a semiconductor device and a manufacturing method therefor. The semiconductor device includes: a base, where a first surface of the base is provided with a first trench and a second trench; a gate, provided in the first trench; a gate insulation isolation structure, provided in the first trench, wherein the gate insulation isolation structure covers the gate at a bottom, sides and a top of the gate; a source doped region, provided in the base, on both sides of the first trench and on both sides of the second trench; a trench conductive structure, provided in the second trench; a source electrode, provided on the trench conductive structure and the source doped region, and electrically connected to the trench conductive structure and the source doped region; and a drain electrode, provided on a second surface of the base. The semiconductor device in the present disclosure, in addition to be conducted through a channel, can also be conducted through the trench conductive structure; thus, conductivity thereof is stronger. Since the channel conducts faster, a turn-on voltage (forward voltage drop) thereof is lower.