The phase changes of the forward-scattered light is explicitly obtained in an isotropic critical chiral fluid by using the Fisher correlation function of density fluctuations, when the incident light is completely linearly polarized above (or below) the horizontal at 45degrees. A new experiment method is suggested to measure the critical exponent for correlation function by using the result of azimuth changes of the scattered light. (C) 2003 Published by Elsevier B.V.