This paper investigates the sensitivity of frequency response analysis (FRA) on the structure of transformer winding. Frequency response of a winding is simulated using the multi-conductor transmission line (MTL) model based on the winding parameter. Subsequently, several responses of the same winding are also simulated with varying its original parameter. This is to observe the winding response sensitivity. This paper also studies the response sensitivity on mechanical deformation for three different windings. It is to determine whether a deformation will produce similar response changes of any winding. Additionally, three statistical indicators are employed to measure the sensitivity and assess the performance of each indicator.