A vertical transistor structure includes a substrate, a plurality of pillars located on the substrate and spaced from each other at a selected distance, a gate line and a plurality of conductors. The pillars are aligned in a straight line in a first direction and have respectively a primary control wall along the first direction and two ancillary control walls perpendicular to the primary control wall. The gate line is connected to the primary control wall in the first direction through a first isolated layer. The conductors are interposed between the ancillary control walls through second isolated layers. By providing the gate line merely on the primary control wall and the conductors to aid the gate line to control ON/OFF of the pillars, problems of etching and separating gate material during gradually shrunken feature size process that are difficult to control etching positions and etching duration can be prevented.