In order to measure the inflight carried loads on external store in flight test, a six component force pylon-balance has been developed. The inflight carried typical loads on external store are provided under the state of steady level flight and normal symmetrical pull-up. The aerodynamic loads on external store have been calculated by the aerodynamic differential coefficients deduced by wind tunnel test data. These results have been analysed and compared; the magnitude and laws are very consistent under the stable state, the difference is worth studing under unsteady state. The pylon-balance is practical and effective for measuring the loads of external stores in flight test.