Abstract: A case of heavy rain in July 1991 was diagnosed with 48-hour three dimensional trajectory of air parcel associated with the high and low level jets. The high level air parcel over the rainfall area is coming from the entrance of high level jet and passing the core of the jet to the exit region. The high level divergence over the rainfall area is related to the deceleration of air motion. The low level warm and moist air is coming from the SSW current, which is convergence and asscending at the front of the core of low level jet. The acceleration of low level air and the intensification of low level jet are associated with the high level divergence due to the reduction of low level pressure.