Abstract: An air-jet driven dynamic balance test apparatus for testing the dynamic balance of minrotors with minimum interference from external vibration noise. The dynamic balance test apparatus comprise a resilient supporting steel sheet having a horizontal bottom portion fastened to a base and an elongated upright body portion extended upwardly from the horizontal bottom portion to carry the sample to be tested. An air-jet generating device is provided to produce a continuous stream of compressed air for rotating the sample about its central axis. The resilient supporting steel sheet contains a resilient section for increasing sensitivity of said test apparatus. The resilient supporting steel sheet contains a resilient section, which can be the resilient steel sheet itself or in the form of a row of through holes or a corrugated section. A detector is mounted on the resilient supporting steel sheet to detect the vibration as the sample is being rotated during testing.