Discussions of the correlation between the residuals of predictand and predictor suggested that the candidate predictors consist of two different parts of Predictors.Predictors of the first part are these that the correlation between the predictand and predictor is better, while the correlation between one and another of the predictors is not good.Predictors of the second part are these that the correlation between the predictapd and predictor is very bad while the correlation between the main predictor and the predictors is best or worst. And a method of selecting predictors which are made up of the candidate predictors is put forward and called the Method suited to the main predictor.