A two-tracer PLIF system was developed to measure fuel stratification in cylinder of a spark ignition engine which is achieved by producing a strong tumbling flow and introducing two fuels through two separate intake ports.Two tracers,3-pentanone and N,N-dimethylaniline(DMA),were doped in two fuels,hexane and iso-octane,respectively.A spectroscopic test result showed that when subject to irradiation by a XeCl Excimer laser(308 nm),3-pentanone and DMA emit fluorescence within different wavelength regions.Their fluorescence can be separated by two band-pass optical filters and recorded into a single intensified CCD camera through a specially designed image doubling system.The advantage of the measurement method is that both fuel distributions in cylinder can be visualized by one shot.Measurement results showed that two fuels were well stratified in the cylinder. A two-tracer PLIF system was developed to measure fuel stratification in cylinder of a spark ignition engine which is achieved by producing a strong tumbling flow and introducing two fuels through two separate intake ports. Two tracers, 3-pentanone and N, N-dimethylaniline (DMA), were doped in two fuels, hexane and iso-octane, respectively. A spectroscopic test result showed that when subject to irradiation by a XeCl Excimer laser (308 nm), 3-pentanone and DMA emit fluorescence within different wavelength regions. Their fluorescence can be separated by two band-pass optical filters and recorded into a single intensified CCD camera through a specially designed image doubling system. The advantage of the measurement method is that both both fuel distributions in cylinder can be visualized by one shot. Measurement result showed that two fuels were well stratified in the cylinder.