Abstract: A spectrum model of the lift force on an oscillating cylinder in uniform stream is presented based on the VIV experiments of a flexible cylinder. The formula is derived as a function of the natural frequency of the cylinder from a Webull probability density function. The fluid-structure interaction is taken into account in the model by inserting the natural frequency of the cylinder into the model. The other parameters in the model are the velocity of flow, reduced velocity, the diameter of the cylinder. The calculated response with the model was compared with measured response of the cylinder tested in experiments. It is shows that the VIV response of the cylinder in uniform current can be predicted by the lift force model proposed in the paper.