Abstract: As a typical building combination form, the grouped cooling towers can have a complicated grouped-tower interference effect. Traditional studies on the grouped-tower interference effect usually emphasized the equivalent static wind load of the tower tubes, while ignored the quantitative analysis on the fluctuating wind pressure distribution patterns. In order to quantify the distribution patterns of the fluctuating wind pressure under the condition of grouped-tower combination, a rectangular arrangement of eight towers with various aerodynamic interference characteristics was selected as the research object. A rigid model synchronizing pressure measurement for the grouped cooling towers was used in the wind tunnel test, and the fluctuating wind pressure on the tower surface at different wind direction angles was obtained. Based on three typical inflow modes, i.e., "windward flow", "crosswind flow" and "leeward flow", the fluctuating wind pressure distribution can be categorized into a "V" type, a "M" type, and a half "V" + half "M" type. The interference mechanism for the fluctuating pressure distribution was explored, and it is found that the interference effect from the fluctuating wind load can be summarized as three types: "weak interference", "asymmetric strong interference" and "symmetric strong interference". A 9-term fitting formula for the fluctuating wind pressure was proposed, and recommended expressions were given according for the three distribution patterns of the fluctuating wind pressure.