In this paper, a 100 Hz planar laser-induced fluorescence system based on the off-shelf commercial laser and self-made intensified camera is presented, which is low cost and maintainable to be applied in practical combustion research. By using this device, 100 Hz continuously planar laser-induces fluorescence laser combustion diagnostics was conducted. To evaluate this device, both laboratorial combustors and a scramjet combustor were studied. In these experiments, the structure of flame and expansion and the oscillation process of combustion can be resolved. [ABSTRACT FROM AUTHOR]