A mathematical model of competition-type lateral flow immunoassay (LFIA) was developed to describe the dynamic process of LFIA.The competition-type LFIA was divided into two categories: TwA-competition-type LFIA and TnA-competition-type LFIA.On the basis of the developed model, the COMSOL software was exploited to simulate the dynamic process of LFIA.The simulation result demonstrated the relationships between the concentrations of substances on the test and control lines and the influence factors.In particular, the influence factors in the TwA-competition-type LFIA included the concentrations of target analyte A (0-20 mol/L) and reporter particle P (0.01-100 mol/L), and the position of the test line (5-20 mm).On the other hand, the influence factors in the TnA-competition-type LFIA included the concentrations of target analyte A (0-20 mol/L) and reporter particle P (0.01-100 mol/L), and the porosity.Experiment result showed that the developed model could be used to explore the influence of the parameters on the test results, and optimize the performance of LFIA.