The correlated color temperature (CCT) is an important parameter to characterize light sources. However, no analytical expression has been provided by international organizations for evaluating the uncertainty of CCT. The uncertainty propagation law and Monte Carlo method are used to analyze the uncertainty of CCT. When using the uncertainty propagation law method, a CCT sensitivity coefficient formula can be derived based on the definition of CCT to evaluate its uncertainty. The variation in CCT due to the change in spectral power evaluated via numerical calculations is used to validate the formula. When using the Monte Carlo method, a group of spectral data can be generalized using numerical simulations. The corresponding CCT and its distribution are calculated to obtain the uncertainty of CCT. The results obtained using the uncertainty propagation law and Monte Carlo method exhibit a good agreement. When the spectral correlation is neglected, the uncertainty of CCT is observed to be proportional to the square root of the wavelength interval.