Abstract: The temperature dependence of Raman Cross section for both stokes and antis-tokes process is discussed. This dependence is used for the in-siru temperature measurement of LiNbO₃ crystal, which turns out to have a good accuracy and to be useful for samples whose temperature can not be measured directly. In addition, according to this dependence, it is found that the order-disorder mechanism of BaTiO₃ phase transition agrees with the experimental results better by comparing the temperature dependence of Raman cross section for several models.