The precursors of functional biomolecules in living cells are synthesized in a bottom‐up manner and subsequently activated by modification into a delicate structure with near‐atomic precision. DNA origami technology provides a promising way to mimic the synthesis of precursors, although mimicking the modification process is a challenge. Herein, a DNA paper‐cutting (DNA kirigami) method to trim origami into designer nanostructures is proposed, where the modification is implemented by a polymerase‐triggered DNA strand displacement reaction. Six geometric shapes are created by cutting rectangular DNA origami. Gel electrophoresis and atomic force microscopy results demonstrate the feasibility and capability of the DNA paper‐cutting method. The proposed DNA paper‐cutting strategy can enrich the toolbox for dynamically transforming DNA origami and has potential applications in biomimetics.  A DNA paper‐cutting (DNA kirigami) method is proposed to trim DNA origami into designer nanostructures, where the trimming is implemented by a polymerase‐triggered DNA strand displacement reaction. Six geometric shapes are created by cutting rectangular DNA origami. Gel electrophoresis and atomic force microscopy results demonstrate the feasibility and capability of the DNA paper‐cutting method.