Three representative models for the prediction of true mass fraction of steam were compared and analyzed to determine most appropriate model that can used to predict the Critical Heat Flux (CHF) for flow of water in uniformly heated vertical tubes. The models studied were Kroeger & Zuber's[1], Levy's[2] and Jafri et al.'s[3]. For the comparison, 188 data points from Beckeret al.[4] (10 MPa data) were selected as a representative sampel from the CHF database that contains a total of 8,912 data points. In case of Kroeger & Zuber vs. Jafri et al., the everage error was 0.33% and the root mean square error was 2.47%. In case of Levy us. Jafri et al., the average and root mean square errors were 1.66%, 2.67% respectively. Jafri et al.'s model can be applied to both uniform and non-uniform heated tubes because it is in a form of rate equation that can easily be used for calculating the true mass fraction of steam along the length of tube.