Based　on　the　theory　of　probability,　with　a　small　cloth　bag　in　the　catalyst　bound　as　the　study　object,　the　model　of　tracer　concentration　distribution　in　the　fixed　bed　was　established　using　the　traditional　Galton　board　model,　and　the　expression　of　the　concentration　distribution　model　in　the　fixed　bed　was　obtained.　The　experimental　setup　was　established　using　KCl　solution　as　the　tracer　and　the　experimental　results　were　compared　with　the　model　predicted　values.　The　experimental　value　fitted　well　with　the　model　predicted　value.　The　influences　of　different　parameters　on　concentration　distribution　in　the　fixed　bed　were　analyzed.　The　trace　concentration　distribution　curve　gradually　became　gentle　with　increasing　catalyst　particle　size　and　increasing　height　of　the　fixed　bed　but　decreasing　liquid　spray　quantity.　©　All　Rights　Reserved.