The RKKY interaction seems to predict a phase transition even in one dimension because it falls off as cos(2k(F)r)/r in the limit 2k(F)r>>1 at zero temperature. However, the coupling constant of the RKKY interaction changes as a function of temperature and decays faster than 1/r as temperature increases. The result of numerical calculation shows that the envelope of this oscillatory interaction decays as exp(-a(T)r)/r(b(T)). The exponent a(T) increases almost linearly and b(T) decreases from 1 as temperature increases. This excludes the possibility of a phase transition due to RKKY interaction in one dimension.