A　mathematical　model　of　sandwich-type　lateral　flow　immunoassay　(LFIA)　is　established　to　describe　the　dynamic　process　of　LFIA　according　to　the　biochemical　principle　of　LFIA　together　with　the　convection-diffusion　equations　and　the　hydromagnetic　equations.　Based　on　the　established　model,　the　COMSOL　software　is　utilized　to　simulate　the　dynamic　process　of　LFIA.　The　simulation　results　not　only　demonstrate　the　relationships　between　the　concentration　of　the　sandwiched　substance　and　the　position　or　the　time,　but　also　analyze　the　influences　of　the　initial　concentrations　of　all　substances　and　the　structure　on　the　performance　of　LFIA　system　when　the　target　analyte　A　is　from　0　to　20　mol/L,　reporter　particle　P　is　from　1　x　10(-2)　mol/L　to　1　x　10(3)　mol/L　and　the　porosity　is　from　0　to　1.　Especially,　within　a　certain　concentration　range,　the　increasing　concentration　of　target　analyte　A　and　reporter　particle　P　will　enhance　the　quantitative　performance　of　LFIA,　and　the　porosity　affects　the　result　by　controlling　the　flow　rate　of　the　test　mixture　and　the　material　contact　in　the　mixture.