As a novel bio-inspired robot configuration, the tendon-driven truss-type bionic mechanical leg necessitates attention to its motion stability control. The dynamic model is established based on its mechanical ontology characteris-tics and Lagranian Mechanics. On this basis, stability analysis is carried out for the nonlinear characteristics of the system, and the research focuses on the motion stability control problem at vertical equilibrium points. In order to achieve the control goal, this study employs the pole placement method to construct a feedback control strategy, while simultaneously developing an interval type-2 fuzzy logic controller in parallel for comparative validation. Verification through numerical simulation shows that the proposed control strategy can effectively achieve stable retention of the bionic leg at the vertical balance point. The experimental results confirm the correctness and effectiveness of the control algorithms and verify the engineering applicability of the proposed control scheme in bio-inspired robotic systems.