The kinetics of non-isothermal transformation from isotropic to anisotropic phases of hydroxyethyl cellulose acetate (HECA) was studied by DSC at different cooling rates. It was found that the modified Avrami equation could be used in study and the exponent n was closed to 1. The rate of transformation increased with decreasing temperature and the apparent activation energy E was about 2.641 KJ/mol. The half-time of transformation t(1/2) was smaller than that of polymer crystallization and increased with temperature. The rate of transformation appears the maximum with temperature and the temperature at the largest rate of transformation shifted towards the low temperature with increasing cooling rate and the kinetic ability of transformation was also enlarged.