Abstract: To investigate the dynamic characteristics of the swirling injector,an experimental system was built.High velocity photographic testing system has been used in the experiment.Original investigation of the velocity pulsation,breakup length and the wavelength of the liquid film in the spray field were tested.It can be concluded that effects of pressure drop and geometric characteristic coefficient of the injector on the axial velocity in the spray field and some parameters about swirling liquid film are significant.Pressure drop and pulsation of feed system will greatly affect the wavelength and the breakup length of the liquid film.Experimental system,testing device and method of the experiment can be used for the investigation of the dynamic characteristics of the injector.