The retention of gas bubbles causes serious damage to the performance of piezoelectric micro-pump, and bubble retention occurs mainly in the pump cavity, thus reducing bubble retention in the pump cavity can greatly improve the reliability of piezoelectric micro-pump. The bubble has been eliminated quickly and effectively through the method of processing lead-flow path in pump cavity. The method has the advantages of easy processing, good universality and strong operability. The relationship between bubble retention and output performance through the pressure of pump cavity and the influence of lead-flow path on bubble retention through pressure drop of the bubble and flow resistance were analyzed. Finally, the effect of lead-flow path on output performance and bubble retention was verified by experiments. The experiment results showed that the output performance of piezoelectric micro-pump can be enhanced through processing lead-flow path in pump cavity, when the lead-flow path width was 2.0mm, the output pressure and output flow reached 17.4kPa and 20.8mL/min, respectively;when the lead-flow path width was 1.1mm and 1.5mm, the piezoelectric micro-pump had a strong ability to eliminate air bubbles. After entering 120 bubbles of 0.02mL, the piezoelectric micro-pump still had a stable output pressure (5.8kPa and 5.6kPa) and output flow (16mL/min and 5.6mL/min). Processing lead-flow path in pump cavity can eliminate the bubbles quickly and effectively and reduce bubble retention in pump cavity.