The additional phase and group delay dispersion (GDD) of a femtosecond laser diffracted by ‘surface-volume-surface’ gratings (SVSGs) are deduced with a ray tracing method. The dependence of GDDs with grating periods and spacings between two transmitting surface gratings are discussed. Results show that the GDD decreases with the grating period increasing, finally it will tend towards a certain value. The GDD increases linearly with the grating spacing increasing. The time-domain properties of a 100 fs pulse laser diffracted by SVSGs with different grating periods and spacings are simulated and analyzed on the basis of Fourier optics. Simulation results show that the overall pulse waveform of 100 fs pulse laser has not deformed; it only appears as the pulse broadens, which agrees with the development of GDD.