Vibrational relaxation processes and data of CO2-N2-H2O laser system up to now are surveyed. The data before 1968 are based on Taylor & Bitterman’s review. The data are treated with weighed least square method to get best fit in the form of log10K=A+BX+CX2+ DX3, and the corresponding coefficients are presented. Using these best fits of data and relaxation model with three modes and four vibrational temperatures based on present work, numerical calculation results of small signal gain of GDL agree with experiments, thus eliminating the error introduced by the uncertainties of relaxation data and modle.