We theoretically investigated the electron dynamics processes of periodic nano ripples formation on fused silica induced by temproally shaped femtosecond laser.The dynamics model for predictions of ripples peirod is proposed by introducing the mechanisms of non-linear ionization and surface plasmon polaritons(SPPs)interaction.The quantitative relation between nano ripples period and temproally shaped pulse separation were obtained by applying the proposed model.It is revealed that the nano ripple peirod can be manipulated by adjusting the temproal separation of the temproally shaped pulses due to the transient adjustment of the wavevecotor matching process during ripple formation via temporally shaped pulses.The theoretical predictions of the ripples period match well with the experimental datum.This study provides for the fundamental understanding of transient formating mechanism of ripples,used for precisely manipulating the ripples period.