The paper aims to execute 10-pm order mechanical displacement measurements using a heterodyne interferometer, a single phase-locked loop (PLL), and a piezoelectric (PZT) flexure stage. It is not a simple task to measure a mechanical displacement of 10 pm or less owing to electronic and environmental noises in the interferometer. The PLL phase meter is designed for a noise floor below 0.1 pm/VHz to reduce electronic noises. The heterodyne ịnterferometer and the PZT stage are designed and placed inside a vacuum chamber with many sealed enclosures. It helps minimize environmental noises for the system. The result shows that the system can achieve mechanical step displacements of 11 pm. Researchers in research institutes and universities have been developing these displacement measuring systems in Vietnam but have not yet reached such a resolution. In Japan, researchers in research centers and universities such as NIST, Department of Mechanical Engineering (NUT) have evolved strongly for the above machines/systems and strived for a resolution of ~10 pm. This Iiterature serves as the basis for the pico-measurement research group students to continue developing and collaborating on research.