Abstract: Calculations of light water reactor cores need to be implemented at a wide range of temperatures.In thermal energy range（below 4eV）,the thermal scattering law for H bound in H₂O is with important effect on the calculations.In the current major evaluated nuclear data libraries,the thermal scattering laws for H bound in H₂O are given at fixed temperatures.The calculations can only performed accurately at those temperatures.In order to improve the accuracy of the calculations of light water reactor cores,the methodology for the generation of the thermal scattering law data at any temperature in the range of 293.6-1000 K based on the IKE model is introduced.A set of thermal scattering laws are generated on the temperature grid at interval of 10 K.With the thermal scattering law data and MC transport code,the k_eff of the benchmark models HMF004 and VENUS3 are calculated at various temperatures.The results show that the generation of the thermal scattering data is correct.