The time-domain properties of ultrashort pulse laser through transmitting volume Bragg grating was studied with Kogelnik’s coupled-wave theory.The dependence between group delay dispersion of transmitting volume Bragg grating and grating parameters was discussed.The influence of group delay dispersion and spectrum clipping on the intensity distribution of diffracted beam in time-domain was studied.The results show that the stretching of diffracted pulse is mainly from the spectrum clipping in the case of input pulse duration of 100 fs,and the strecthing is influenced by spectrum clipping and group delay dispersion at the input pulse duration of 10 fs.