Abstract: Based on the rigid pressure testing model of double towers structures, the paper studied the characteristics of wind load acting on a double tower structure by wind tunnel tests in simulated atmospheric boundary layers. By analyzing shape coefficients, wind induced interference effects were studied. Results show that block effect and slit-width effect are significant. The negative wind pressure on the interfered structure is very low due to the existing of the upwind interfering structure. The negative wind pressure on the wall facing one tower becomes much higher when the interfering structure is parallel to the interfered structure along the wind direction due to the slit-width effect. The slit-width effect becomes smaller with the increase of building height.