Variant design method

The invention relates to a variant design method. The method comprises the following steps of: establishing a product model; performing product structure variant design, comprising object property incidence relation description and variant design process; determining basic properties in the variant design process, determining or calculating the values of derived properties according to a restriction relation set between the basic properties and the derived properties, and driving a three-dimensional model in a computer-aided design (CAD) system through the basic properties and the derived properties of an object property table to perform variant design; and finally, performing process variant design. The method has high automation degree and is simple in operation.