This paper summarizes a complete analysis about vibrational characteristics of a spinning simply supported cracked shaft with fluid medium at finite region. The damping effect occurs due to external fluid is integrated in the existing analysis, with the help of navier stokes equation. The simply supported cracked shaft is analyzed by the influence coefficient strain energy method. Here we have changing the parameter of shaft i.e. damping viscosity of fluid and the length of the shaft which accountable for the alteration of the amplitude of vibration.