In order to reduce the backward motion of the piezoelectric actuator and realize the miniaturization of the piezoelectric actuator, a walking-type piezoelectric actuator with vertical placement of flexible mechanism is proposed in this work. Two parallelogram flexible mechanisms are placed vertically to complete the "walking" movement of the actuator, and two flexible mechanisms are placed vertically to effectively reduce the volume of the actuator. The structure is simulated and analyzed by finite element method (FEM). In addition, the performance of the piezoelectric actuator is compared by experiments. Under the conditions of U=120V, f=1Hz, φ=160°, the forward and reverse vertical load of the piezoelectric actuator are 10kg. The maximum horizontal resistance of the forward motion is about 4.5N. In φ=160° condition, the maximum forward motion speed of the slider is 2705.85µm/s. Under the same voltage and frequency conditions, the forward motion vertical load of the single-driving foot piezoelectric actuator is 1600g, the maximum horizontal resistance of the forward motion is about 0.8N, and the maximum speed of the forward motion is 403.11µm/s. The experiment results show that the walking type piezoelectric actuator with the new flexible mechanism vertically placement has better working performance than the single-driving foot piezoelectric actuator in all aspects. Compared with the walking type piezoelectric actuator with traditional flexible mechanism placement method, the volume of the vertically placed flexible mechanism piezoelectric actuator proposed in this study is only 90×70×40mm, which significantly reduces the volume of the walking type piezoelectric actuator, and has certain significance for the miniaturization and market application of the piezoelectric actuator.