Abstract: we coat single-walled carbon nanotubes（SWCNT） and polymethylmethacrylate（PMMA） solution in quartz substrate by using rotation coating,which forms SWCNT film After drying on constant temperature.Using scanning electron microscopy（SEM） observes the distribution of SWCNT,and researching the influence of the film,which the different solubility and rotating speed arouse,Using Infrared spectrometer tests the linear transmission of the sample films.The experimental results show that this kind of film fits to be used for saturable absorber.