In this paper we have used parallel moire′ deflectometery in z-scan configuration and z- scan methods to measure nonlinear coefficient of ferrofluid. Values obtained from  two methods are compared. The value of nonlinear coefficient is obtained to be 72×10^-3 cm/W in z-scan method. The positive sign illustrate two photon absorption process. The radius of curvature of laser beam and phase changes are extracted and nonlinear coefficient was in good agreement with the value of z-scan method.