Based on the earlier reports that the saturation model was the most optimal model for prediction of relationship between age and body weight,and the linear model is the most optimal model for prediction of relationship between body weight and backfat thickness of three commercial pig breeds.However,in this study,we adjusted the equations for days and backfat thickness at 50 kg body weight.The robustness for the adjusted equations were evaluated by the simple correlation analysis(CORR) and canonical correlation analysis(CANCORR),between the early and whole period revision value,and the results all reached the extreme difference.It proved that the adjusted equations were suitable,and statistically evident between the early and the entire period traits.Additional,we chose the typical comprehensive index model to carry on comprehensive assess for early and entire period performance,and the Spearman’s rank correlation reached the extreme difference for total selection index between two periods.It showed that the early selection was viable,had very high consistency with the entire period selection under definitely choosing strength.These revised expressions of the expected traits had potential application for breeding selection in farm.