In order to solve the airport surface confliction problem in large airports, a variable structure interacting multiple model algorithm based on runway taxiway system constraint and ATC order constraint is applied to the tracking of field targets. We first establish the methods for mathematical modeling of complex taxi structures, tracking status fixing under the taxi structure constraint, and adaptive matching of aircraft and taxiing system based on ATC order constraint. In dealing with the runway matching and model switching, the maximum a posteriori (MAP) estimations of runway taxiway system constraint and ATC order constraint are utilized to activate and terminate the model set. A new method, which combines the variable structure interacting multiple model with the MAP, has been proposed for improving the tracking performance. Simulation results demonstrate that the proposed method is more effective than the interacting multiple model and the variable structure interacting multiple model, leading to superior tracking accuracy.