Surface fluctuations at downstream locations of a hydraulic jump with Froude number of 1. 97 are measured and analyzed Spectra various of the surface motion show that bands of somewhat normally distributed energy centering at particular frequencies exist at all measured locations. The identified main frequency decreases in the downstream direction and it reaches to a local minimum at about the jump end location then it increases again slightly. These periodic characteristics in the surface fluctuation are believed to highly relate to the cyclic mechanism of the surface roller formation as the released bulk eddies from it could interact with the free surface downstream of the jump and leave characteristic signals.