Wind tunnel tests were conducted to study the wind induced interference effect on two adjacent 200m high super large cooling towers based on full aero-elastic model. The test result indicated that interference effect significantly increased resonance response, but background response played a major role in the total displacement response. The largest average response of the downstream tower reduced due to the shielding effect caused by the upstream tower when the towers were "in tandem". However, wind-induced interference resulted in an addition on root of variance which made the maximum response basically identical to the single tower. Also, the max response magnification factor was found when the tower was in the wake of upstream tower. In addition, the interference factor defined by the max response of the tower could guarantee the max response produced by the loads equal to single tower loads multiplied by the interference factor consistent with group towers, and to the recommended interference factor which took into account the frequency of wind direction basically in accordance with the value in code.