Abstract: To address the instability in flow conductance regulation of piezoelectric micro-adjustment valves used in vacuum systems, this study designs a flow conductance measurement system based on the constant-volume method, investigating the effects of excitation voltage amplitude, waveform, and application history on the flow characteristics of a typical piezoelectric micro-adjustment. Experimental results reveal significant hysteresis in the flow conductance-excitation voltage cyclic curve, where the flow conductance during voltage reduction was notably higher than during voltage increase, likely due to the time-dependent relaxation of piezoelectric ceramic domain structures and residual stress release. A high voltage pre-excitation with 100 V is applied, leading to remarkable improvements in the repeatability of flow conductance at typical voltages. This indicates that pre-excitation optimizes domain structure alignment and residual stress distribution consistency, reducing deformation hysteresis. The research uncovers the critical influence of excitation voltage application history on flow regulation performance, providing experimental evidence and insights for enhancing pressure control precision in vacuum systems.