Active ankle dorsiflexion in swing phase to ensure foot clearance, and resistive dorsiflexion for heel rocker function to prevent foot slap are important for a normal human gait. Stroke patients with hemiplegia have motor deficiency in their paralyzed side, and thus could not voluntarily generate enough dorsiflexion force. In this paper, we present our design of a light-weighted high dorsiflexion supportive robotic technology. It supports swing phase dorsiflexion with a McKibben-type artificial muscle, and supports heel rocker function with a tension spring. A pilot clinical trial shows the immediate improvement of dorsiflexion in swing phase by supporting high dorsiflexion angle in intervention, and the other pilot clinical trial shows the effects of heel rocker function support with lessened angular velocity of ankle plantarflexion and knee flexion.