A method simulating an occurrence of an air pocket in an object to be coated is provided with steps of: setting an initial boundary element; setting an element having a common nodal point with the initial boundary element as a flanking element; analyzing the flanking element; setting the analyzed flanking element as a secondary boundary element; setting an element having a common nodal point with the secondary boundary element as a flanking element; analyzing the flanking element; and determining whether there is a remaining flanking element. When there is a remaining flanking element, a secondary boundary setting step and a second analysis step are repeatedly performed, until no remaining flanking element is determined.