Abstract: A pressure-measured sectional model wind tunnel test of a rectangular cylinder with aspect ratio 5 was performed. The changing rule for the spanwise correlation of an aerodynamic force versus a spanwise distance and a wind attacking angle was studied. The study results show that the spanwise correlation coefficient of an aerodynamic force becomes smaller with a larger spanwise distance. Under the same spanwise distance, the spanwise correlation coefficient of a lift force is greatest, the spanwise correlation coefficient of a torque is smaller, and the spanwise correlation coefficient of a drag force is smallest. The spanwise correlation coefficient between a lift force and a torque attains the maximum value in a zero degree wind attacking angle, and it becomes smaller with a larger wind attacking angle.