Abstract: Aimed at the searching of similar 2D sheet metal parts,a searching strategy suitable for unfolded sheet metal parts is presented.Based on the analysis on the characteristics of the sheet metal parts,thirty six key features commonly used in design are extracted and a model to represent their position relationship is built.By applying the relative position triangles between key features,the model can be coordinate and rotation independent.An algorithm used for searching the relative positions of the key features of sheet metal parts is presented.Case studies verify that the method suggested is able to meet the searching requirements of sheet metal parts and possesses potentials in practical application.