The hybrid operations of surfacetoair missile is an necessary choice of dealing with information air attack and improving groundairdefense integrated operations effectiveness. The basic mode and criterion of surfacetoair missile hybrid deployment are explained. The main factors of deployment decision model are analyzed based on System Dynamics (SD) theory, including the airattack parameters, firepower unit deployment and equipment capabilities. The judgment regulation of fire condition, variable setting and inflection relation in SD simulation model are proposed. Taking "one intermediate and two short range" hybrid deployment mode as an example, the SD model of surfacetoair missile hybrid deployment decision is built, including the model structure diagram and important variables operation relation. By setting the typical parameters and countermeasure sequence, the SD model simulation experiment is executed and the important variables' simulation results are acquired. And the meaning and application of simulation results are discussed. The case application shows that the decision SD model is feasible and effective.