This article presents a practical method for validating generator saturation factors together with direct-axis model parameters by collectively using several field test results conducted on the same generator. The method is devised from many years of WECC/NERC synchronous generator model validation experience. Model validation following this method can significantly eliminate the mismatch between the computer simulation results and field measurements for tests on generator direct-axis model parameters. The effectiveness of this method is demonstrated by comparing field test results on a hydro-turbine generator with computer simulation results using validated generator model parameters. Future application of the method is proposed and discussed.