The influence of different chromaticity coordinate spaces and different scale factors derived from the tristimulus values L, M, and S of the cone response on the calculation of correlated color temperature (CCT) is studied, and the difference between the calculated CCT and the standard CCT is compared. Tests are carried out on a data set containing 401 spectral power distributions collected by Houser et al. The test results show that the u_c-v_c space directly derived from the calculated L, M, and S when the scale factors are all 1 is the best, and the absolute differences of the mean CCT, the median CCT and the maximum CCT are 48, 31 and 851 K, respectively. If the L, M, S are converted to the u_F-v_F space derived from the tristimulus value space X_FY_FZ_F defined by the color matching function to calculate the CCT, the mean CCT difference, the median CCT difference and the maximum CCT difference between the calculated CCT and the standard CCT are 42, 21 and 540 K, respectively.