This paper presents the design of a new compact 1- DOF compliant stage driven by a piezoelectric actuator (PEA) for micro/nano-positioning in vertical direction. In order to fulfill the design requirement and to improve the compactness and output directionality of the stage, a series of design processes are presented. In particular, an orthogonal compound bridge-type (OCBT) amplifier is introduced to amplify the displacement of the PEA. It can significantly reduce the height of the stage, leading to a compact design. The design variables are determined by analyzing the mechanism. These design variables are optimized by multi-objective genetic algorithm (MOGA) based on finite-element analysis (FEA). The optimal design results in the stage dimension of 58×20×15.5 mm3. Performance evaluation is conducted by FEA analysis. Results show that the 1-DOF stage is able to provide a maximum displacement of 181.18 μm, which is more than 12 times the input displacement of PEA. Payload testing results indicate the stage can support a maximum load of about 80 N.