In this letter, a new band-splitting method for two-band speech model is proposed, whereby a score function based on the subband periodicity is calculated for each harmonic band and the band of maximum score is selected as the band-splitting frequency. Using the score function, tracking technique is applied to the algorithm for the continuity of the band-splitting frequencies between neighboring frames. This method has proven to be robust to the inaccuracy of pitch estimation and the frequency resolution problem in low-pitched speech.