Abstract: As a typical small batch and multi-varieties product, variantional design of small agricultural machinery was an effective approach to reduce cost and shorten developing cycle. Aiming at the problem that the partial variation to meet customer requirements could lead to conflict of constraints, variantional design approach based on constraints reconfiguration of templates was proposed. On the basis of existing templates, the attributes of objects and the constraints among objects of template were represented by hypergraph. New rules database was created through re-grouping template objects and reconfiguring rules of constraint so as to configure concrete product structure on the basis of new templates. Applying the approach to variantional design of small agricultural machinery demonstrates the feasibility of the results.