Abstract: When reinforced concrete chimneys is strengthened with prestressed hoops, uniformly distributed radial pressures can be generated on interfaces. Based on cylindrical shell theory, the calculating formulas of circumferential pressures, circumferential stresses and pressure influence height on chimney tube generated by radial pressure are obtained. The numerical results show that the distribution of circumferential stress is curvalinear. Circumferential stress reaches the maximum, at about -1.0MPa, on the belt in contact with the hoop. It increases with the rise of hoop position, and decreases to zero at the start-stop point of pressure influence height. The pressure influence height decreases with the rise of hoop position and the reduction of hoop radius, the average value of which is 2.8m. The reasonable hoop distance can be obtained according to pressure influence height.