Actual rainfall runoff modeling involves two kinds of procedures: identification of the optimum parameters and selection of suitable data. Although many reports described automatic procedures to obtain the optimum parameters of models, few proposed a suitable procedure of data selection. In these papers a new multiple regression model which enables to identify the optimum parameters of linear runoff and select suitable data for the modeling of linear runoff is described. The method based on the robust statistical theory is referred to as RFMD (robust fixed maximum discharge) method developed in the past decade. In this paper, this method was tested by using the original data of the Muda and Pedu dams in Malaysia. Compared to the FMD method, the RFMD method can supply similar models for long-term analysis and improved models for short-term analysis which contains irregular data.